Parties can be removed from a matter record by selecting Parties on the right side of the screen under Team, Firms, Parties in the Matter Navigation Bar.

In the Active List view, click on a party name.

Select the icon. A confirmation window pops up; press OK to continue.

Important Note: If a party has a payment on file, the account will be locked (). Selecting the  icon does not erase the party from the database itself, it only removes its association with that particular matter.