IDX Broker developer partners have the ability to make changes to client accounts right from the dashboard.
Log-in to your partner dashboard and visit --> Clients --> Client Search
To Cancel:
Click Icon 
on the far left and then under Account Info At a Glance is a blue hyperlink labeled cancel account.
NOTE: This can be done by all developer partners and is the only way to cancel an account with partner billing control enabled.
To Upgrade:
Click Icon on the far left and then under Management is an option for Upgrade Client
NOTE: This option is only available if partner billing control is enabled.
If you do not have partner billing control enabled, then log-in to the client account and visit the upgrade center as the client.