Changing a user's billing plan takes place on the Edit User screen:
- Go to your Control Panel's Users and Groups menu.
- Click the Actions button next to the user in question, then click Edit.
- Select a billing plan for the user from the billing plan drop-down menu.
- Click the Save button.
Editing a billing plan that is associated with more than one user will affect all users attached to it. If you wish to only affect that user then copy the billing plan and associate it only with the single user.