Edit or Delete a Task name in Timesheet

Edit or Delete a Task name in Timesheet

It seems the task names for timetracker are isolated within each account we have added in the project/timetracker area.
So can we edit or delete the task names attached to these account individually. the pricing for us changes sometimes on our rates and need the task name to remian the same but the rate amount needs to change.
 
How can we accomplish this?
 
Thanks!
 
Robert