This video outlines the steps below:

Step 1. Go to Administration>Account Settings. Scroll down to Support Access.

Step 2. Click [GRANT ACCESS] button. You have a right to restrict the time period you are giving us permissions to access the account.

Step 3. When the access is granted, you will see the name of the person who has given our support permissions to access the account and the expiry date. 

You can revoke access at any time. Instead of the green button there will appear a red one saying "REVOKE ACCESS". Only click this button if you want to revoke it before the expiry date:

If the access has been cancelled before, you can grant it once again by clicking the [GRANT ACCESS] button:

The records of all these operations are kept in your account Administration> Support Access tab: