How do I manage PBX Settings for my Customer accounts?

Partners are able to manage PBX Settings for their customer's accounts directly from the Partner Portal.

Log in to the Partner Portal with the credentials provided to you by GreenLink.
On the left hand side, scroll down on the menu options until you find CUSTOMERS.
Click on it and wait for the page to load.
Once it loads you will see all your current customer accounts, click on MANAGE, on the left hand side next to any of your customer accounts.

If you receive this error message when trying to access one of your customers:

Error You are not authorized to manage this Customer. Please contact them and/or support in order to request access.

This is means the Customer when their agreement was signed they choose to manage their own account and remove the access to the partner.