This feature is available in Enterprise and Ultimate editions.
You can move (or reassign) workitems from one team to another following these steps.
Go to Release > Team Scheduling.
Click the plus sign (+) next to a team to view all workitems assigned to the team.
Select an item you want to move and simply drag and drop it onto the team to which it is to be reassigned. The system adjusts cumulative counts and estimates for both teams.
Click to open the work item and click the edit icon in the Team field.
Click the minus sign (-) next to the currently assigned team and select a team from the suggested teams list.