RemoveFullAccess.ps1

$UserCredential = Get-Credential
$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $UserCredential -Authentication Basic -AllowRedirection
Import-PSSession $Session
Connect-MsolService

#
# You only need to run this bit once to populate the users ids

# Get-Mailbox | Get-MailboxPermission -User administrator@pureinnovations.co.uk |select Identity |export-csv C:\scripts\pure-users.csv

#
#
#

$listofusers = Import-Csv -path C:\scripts\pure-users.csv

foreach ($userid in $listofusers) 
{get-mailbox -Identity $userid.Identity |Select-Object PrimarySmtpAddress

#Do what you want in here dave ($userid.Identity) is the email addy

Add-MailboxPermission -Identity $userid.Identity -User administrator@pureinnovations.co.uk -AccessRights FullAccess -AutoMapping $False -InheritanceType All -Confirm
}