Changing the Task manager on a Task

Hello,

In Award management screen - there is a way to end date a particular employee like the award manager and enter a new person in that role in case of a change in position.

However, on the Project - Tasks - there is no option to end date a task manager. 

1. Is is okay to change the task manager when there are some expenditures pending if a new manager has been assigned to the task ?. Will it have any impact on unprocessed expenditures ?

2. How can we retrieve the historical data of both the task managers that were assigned to the task.