To replace a project team member you must first make sure that the replacement resource has already been added to the project team. Next:

Click on the "Replace resource" icon on the toolbar

In the "Resource replacement" dialog box that opens, select the resource to be replaced and the replacement resource:

Once the replacement resource has been selected, all assignments made to the replaced resource will be re-assigned to the replacement resource.

If the old resource already have Actuals, there will be no changes in the planner. The current

resource will stay in place with it's remaining workload.

If the old resource do not have any Actuals, it will been replaced by the new resource. The new resource get all of the planned and remaining workload form the old one