Grant an Exchange 2010 Administrator Paswordless Access to User’s Mailbox (PowerShell)

This does not include “send on behalf of” rights. 

Assign full access permissions to Exchange administrator:

[PS]> Add-MailboxPermission [email protected] -User administrator -AccessRights FullAccess -InheritanceType All

Remove permissions from Exchange administrator:

[PS]> Remove-MailboxPermission [email protected] -User administrator -AccessRights FullAccess -InheritanceType All

Go to Exchange Control Panel on https://exchange.example.com/ecp and select “Manage Another User”.