Enter Setup mode by clicking Setup link located on a top-right corner of a screen.
If you are going to decrease the number of users, please deactivate extra users.
To do this, select Sharing / Roles > Manage Existing User Shares from the left-side menu. You may either deactivate the user by editing his/her record and setting the Role to "--None--" or delete the user by pressing Del button.
Check your current subscription by selecting Application > Manage Subscription from the left-side menu. Press Update Subscription button.
Change the number of users and click Next until you reach last step of the subscription wizard.
As a result, a new master order will be created that will overwrite a previous master order and will become a base for all subsequent charges and receipts. You card won't be charged until 1 day before a due date.
Invite new users by selecting Sharing / Roles > Share with Additional Users