Basically, you can't.
Advocates do not have the ability to change a customer's autoship through their back office. The customer either needs to manage their autoship on their own, or they can get assistance from Customer Support to complete this request.
For security purposes, we need confirmation from an account holder to make changes on an account.
As an Advocate, we understand the desire to streamline and make things as simple as possible for your customer. However, Green Compass priorities account security. If you would like to initiate a change on an autoship on behalf of a customer, we will need the customer to CC'ed into the ticket from their email address on file for the account. Once we have their confirmation, we are happy to assist.
(Hint: Feel free to share helpful links from our HelpDesk with your customers with directions on how to cancel their own autoship!)