To change the team member assigned to a specific project role, do the following:
Navigate to the Project Resources page by selecting (Project #)> Go To> Resources > Listing or by clicking the Resources link on the Left Navigation Bar within a particular project. The Project Resources page is displayed.
Click on the appropriate Project Role and from the Actions column select Edit.
On the Edit Team Member Info page, select the user from the Possible Choices drop-down list who is to be assigned to the selected role.