Following along in MyCase is recommended as you read the article.
Overview
In the instance that you need to remove a client or contact from a case for any reason, you can do so in 8am™ MyCase.
Unlinking a Client/Contact
First, open the Case Details page for the case that you'd like to unlink someone from. Click the Contact & Staff Link button. You will be taken to a list of all the clients, contact, and staff who are linked to the case.
Notice the dark gray X to the right of everyone's name. Click the gray X to unlink the person from this case. You will be asked to confirm that you'd like to unlink this person from the case.
The Billing Contact can not be unlinked from the case unless you deselect them as the Billing Contact first.
Unlinking someone from a case does not delete that person in MyCase. They will still be listed as a contact in your contact database.