1st Step: Postpone a session.
Go to "Schedule" or "Calendar", click on the session you want to postpone then click on "Edit".
Select the new date of the session, in the "Times and dates" boxes.
2nd Step: Postpone several sessions at the same time.
Do the same manipulation as for Step 1 > Select "Modify all similar sessions according to these new conditions" > Click on "Continue".
This will postpone all the sessions in the same way.
