You have the ability to Enable or Disable Roommate Matching at any time. To do this, from the Staff Dashboard:
Click the "Setup" tab
Click the "Matching Options" tab
Toggle "Lock Roommate Matches" On or Off
An Unchecked box means that students will be able to request others to be their roommates (the roommate request button will be visible), and they will be able to change existing roommate groups.
A Checked box means that you will be Locking Roommate Groups. Student will not be able to request others as roommates (the roommate request button will be hidden), and they will not be able to make any changes to existing roommate groups.
You may toggle Roommate matching on and off as many times as you need.