diff --git a/src/stores/chat.ts b/src/stores/chat.ts
index e5df83f..4930423 100644
--- a/src/stores/chat.ts
+++ b/src/stores/chat.ts
@@ -1,8 +1,9 @@
 import { defineStore } from 'pinia';
 import { computed, ref, type ComputedRef, type Ref } from 'vue';
-import type { Document, ChatMessage } from '@/types';
+import type { Document, ErrorDetails, ChatMessage, ReformulateResponse } from '@/types';
 import { basePostAxios } from '@/utils/fetch';
 import { getQueryParamValue } from '@/utils/urlsUtils';
+import { RELEVANCE_FACTOR } from '@/utils/constants';
 import { getFromStorage, saveToStorage, clearFromStorage } from '@/utils/storage';
 import i18n from '@/localisation/i18n';
 import type { AxiosResponse } from 'axios';
@@ -10,7 +11,6 @@ import { useFiltersStore } from '@/stores/filters';
 
 // CHAT STATUSES
 export const CHAT_STATUS = {
-  ERROR: 'ERROR',
   EMPTY: 'EMPTY',
   REFORMULATED: 'REFORMULATED',
   REFORMULATING: 'REFORMULATING',
@@ -28,13 +28,14 @@ export const useChatStore = defineStore('chat', () => {
   const chatInput: Ref<string> = ref('');
   const chatMessagesList: Ref<ChatMessage[]> = ref(getFromStorage('chat') || []);
   const questionQueues: Ref<string[] | null> = ref(getFromStorage('questionQueues'));
-  const sourcesList: Ref<Document[]> = ref(getFromStorage('chatSources') || []);
+  const sourcesList: Ref<Document[] | null> = ref(getFromStorage('chatSources') || []);
   const reformulatedQuery: Ref<string | null> = ref(getFromStorage('reformulatedQuery'));
+  const queryToSearch: Ref<string | null> = ref(null);
   const storedConversationId: Ref<string | null> = ref(localStorage.getItem('chatConversationId'));
   const storedMessageId: Ref<string | null> = ref(localStorage.getItem('chatMessageId'));
 
   const isChatEmpty: ComputedRef<Boolean> = computed(() => chatMessagesList.value.length === 0);
-  const chatStatus: Ref<(typeof CHAT_STATUS)[CHAT_STATUSES_TYPE]> = ref(
+  const chatStatus: Ref<CHAT_STATUSES_TYPE> = ref(
     isChatEmpty.value ? CHAT_STATUS.EMPTY : CHAT_STATUS.DONE
   );
 
@@ -43,6 +44,8 @@ export const useChatStore = defineStore('chat', () => {
 
   const storedSubject: Ref<string | undefined> = ref(getFromStorage('chatSubject') || undefined);
 
+  const corpora: Ref<ReducedCorpus[]> = ref([]);
+
   const clearSubject = (): void => {
     storedSubject.value = undefined;
     clearFromStorage('chatSubject');
@@ -80,6 +83,10 @@ export const useChatStore = defineStore('chat', () => {
     saveToStorage('reformulatedQuery', query);
   };
 
+  const setQueryToSearch = (queries: string): void => {
+    queryToSearch.value = queries;
+  };
+
   function setQuestionQueues(messages: string[]): void {
     questionQueues.value = messages;
     saveToStorage('questionQueues', messages);
@@ -89,6 +96,120 @@ export const useChatStore = defineStore('chat', () => {
     chatInput.value = '';
   }
 
+  async function reformulateQuestion(query: string) {
+    try {
+      chatStatus.value = CHAT_STATUS.REFORMULATING;
+      const bodyContent = {
+        history: getMessageHistory.value,
+        query: query
+      };
+
+      const reformulate: AxiosResponse<ReformulateResponse> = await basePostAxios(
+        '/qna/reformulate/query',
+        bodyContent
+      );
+
+      if (!reformulate || !reformulate.data) {
+        chatStatus.value = CHAT_STATUS.ERROR;
+        return;
+      }
+
+      const { data } = reformulate;
+
+      if (data.QUERY_STATUS === 'REF_TO_PAST') {
+        shouldFetchNewDocuments.value = false;
+        chatStatus.value = CHAT_STATUS.SEARCHED;
+        return;
+      }
+
+      if (data.QUERY_STATUS === 'INVALID') {
+        chatStatus.value = CHAT_STATUS.ERROR;
+        return;
+      }
+
+      shouldFetchNewDocuments.value = true;
+
+      const reformulatedQuery = reformulate.data.STANDALONE_QUESTION;
+
+      if (!reformulatedQuery) {
+        // add error message
+        return;
+      }
+
+      setReformulatedQuery(reformulatedQuery);
+      setQueryToSearch(reformulatedQuery);
+      chatStatus.value = CHAT_STATUS.REFORMULATED;
+    } catch (error: unknown) {
+      chatStatus.value = CHAT_STATUS.ERROR;
+      const { message, code } = (error as ErrorDetails).response.data.detail;
+
+      if (code === 'LANG_NOT_SUPPORTED') {
+        chatMessagesList.value.push({
+          role: 'assistant',
+          content: `${i18n.global.t('error.LANG_NOT_SUPPORTED.title')} ${i18n.global.t(
+            'error.LANG_NOT_SUPPORTED.description'
+          )}`
+        });
+      }
+
+      if (code === 'INVALID_QUESTION') {
+        chatMessagesList.value.push({
+          role: 'assistant',
+          content: message
+        });
+      }
+    }
+  }
+
+  async function fetchSources(): Promise<void> {
+    if (
+      (storedSubject.value && !subjectHasChanged.value) ||
+      !reformulatedQuery.value ||
+      !shouldFetchNewDocuments.value
+    ) {
+      return;
+    }
+
+    const { sdgFilters, sourcesFilters: selectedCorpus } = useFiltersStore();
+
+    try {
+      chatStatus.value = CHAT_STATUS.SEARCHING;
+      const sourcesResp: AxiosResponse<Document[]> = await basePostAxios(
+        `/search/by_slices?nb_results=10${
+          storedSubject.value ? `&subject=${storedSubject.value}` : ''
+        }`,
+        {
+          query: queryToSearch.value,
+          relevance_factor: RELEVANCE_FACTOR,
+          sdg_filter: sdgFilters,
+          corpora: selectedCorpus
+        }
+      );
+
+      subjectHasChanged.value = false;
+
+      const { data: sources, status: sourcesStatus } = sourcesResp;
+
+      if (sourcesStatus === 204) {
+        chatStatus.value = CHAT_STATUS.NO_RESULTS;
+        // no result
+        return;
+      }
+
+      if (sourcesStatus === 200 && sources === null) {
+        chatStatus.value = CHAT_STATUS.NO_RESULTS;
+        // no result
+        return;
+      }
+      chatStatus.value = CHAT_STATUS.SEARCHED;
+
+      sourcesList.value = sources;
+      saveToStorage('chatSources', sources);
+    } catch (error) {
+      chatStatus.value = CHAT_STATUS.ERROR;
+    }
+  }
+
   function storeConversationId(conversationId: string) {
     if (conversationId !== storedConversationId.value) {
       localStorage.setItem('chatConversationId', conversationId);
@@ -104,6 +225,37 @@ export const useChatStore = defineStore('chat', () => {
     }
   }
 
+  async function getNoStreamAnswer(userMsg: string) {
+    chatStatus.value = CHAT_STATUS.FORMULATING_ANSWER;
+    const bodyContent = {
+      conversation_id: storedConversationId.value,
+      sources: sourcesList.value || [],
+      history: getMessageHistory.value,
+      query: userMsg,
+      ...(storedSubject.value && { subject: storedSubject.value })
+    };
+
+    const respBody = await basePostAxios('/qna/chat/answer', bodyContent);
+
+    chatStatus.value = CHAT_STATUS.FORMULATED_ANSWER;
+
+    chatMessagesList.value.push({ role: 'assistant', content: respBody.data.answer });
+    saveToStorage('chat', chatMessagesList.value);
+    storeConversationId(respBody.data.conversation_id);
+    storeMessageId(respBody.data.message_id);
+
+    const newQuestions: AxiosResponse<{ NEW_QUESTIONS: string[] }> = await basePostAxios(
+      '/qna/reformulate/questions',
+      {
+        history: getMessageHistory.value,
+        query: reformulatedQuery.value
+      }
+    );
+    chatStatus.value = CHAT_STATUS.FORMULATED_ANSWER;
+
+    setQuestionQueues(newQuestions?.data['NEW_QUESTIONS']);
+  }
+
   async function fetchRephrase() {
     chatStatus.value = CHAT_STATUS.FORMULATING_ANSWER;
     // get the content of the message which the role is assistant
@@ -127,39 +279,12 @@ export const useChatStore = defineStore('chat', () => {
     chatStatus.value = CHAT_STATUS.DONE;
   }
 
-  async function getAgentAnswer(userMsg: string) {
-    const { sdgFilters, sourcesFilters: selectedCorpus } = useFiltersStore();
-    const body = {
-      query: userMsg,
-      threadId: storedConversationId.value,
-      corpora: selectedCorpus,
-      sdg_filter: sdgFilters
-    };
-
-    const { data } = await basePostAxios('/qna/chat/agent', body);
-
-    chatMessagesList.value.push({ role: 'assistant', content: data.content });
-    if (data.docs) {
-      sourcesList.value = data.docs;
-    }
-
-    storeConversationId(data.conversation_id);
-    storeMessageId(data.message_id);
-
-    chatStatus.value = CHAT_STATUS.FORMULATED_ANSWER;
-  }
-
-  async function getNewQuestions(userMsg: string) {
-    const newQuestions: AxiosResponse<{ NEW_QUESTIONS: string[] }> = await basePostAxios(
-      '/qna/reformulate/questions',
-      {
-        history: getMessageHistory.value,
-        query: userMsg
-      }
-    );
-
-    setQuestionQueues(newQuestions?.data['NEW_QUESTIONS']);
-  }
+  const noResultsAnswer = () => {
+    chatMessagesList.value.push({
+      role: 'assistant',
+      content: i18n.global.t('chatNoResults')
+    });
+  };
 
   async function onSendMessage(message: string): Promise<void> {
     // checks if can be sent
@@ -170,18 +295,41 @@ export const useChatStore = defineStore('chat', () => {
       return;
     }
 
+    // adds message to history
     addToMessageList({ role: 'user', content: message });
 
     try {
-      chatStatus.value = CHAT_STATUS.FORMULATING_ANSWER;
-      await getAgentAnswer(message);
-      await getNewQuestions(message);
+      // rephrases question
+      await reformulateQuestion(message);
+      if (chatStatus.value === CHAT_STATUS.ERROR) {
+        chatMessagesList.value.push({
+          role: 'assistant',
+          content: i18n.global.t('chatProvideValidQuestion')
+        });
+      }
+
+      // gets documents
+      await fetchSources();
     } catch (error) {
-      chatStatus.value = CHAT_STATUS.ERROR;
       console.error(error);
+      chatStatus.value = CHAT_STATUS.ERROR;
+    }
+    if (chatStatus.value === CHAT_STATUS.NO_RESULTS) {
+      noResultsAnswer();
       return;
     }
 
+    if (sourcesList.value?.length) {
+      try {
+        // gets new questions & answer
+        // await fetchChatAnswer(message);
+        await getNoStreamAnswer(message);
+      } catch (error) {
+        chatStatus.value = CHAT_STATUS.ERROR;
+        console.error(error);
+        return;
+      }
+    }
     chatStatus.value = CHAT_STATUS.DONE;
   }
 
@@ -211,6 +359,7 @@ export const useChatStore = defineStore('chat', () => {
     chatMessagesList,
     questionQueues,
     sourcesList,
+    corpora,
     reformulatedQuery,
     onSendMessage,
     fetchRephrase,