Use the Involved/Assignees page to temporarily remove a user from a project, or to reassign a user to a project. There are certain situations when you might need to end or temporarily end an assignee's participation in a project. For example, if the assignee's workload needs to be adjusted, you may give the assigned projects to a different user.
Unassigning assignees instead of deleting them is useful so that you have a record of the project assignment history.