Delegate in workflow

System

Is delegation supported in TS workflows?
e.g. when an approver goes on leave, he might nominate another TS user to be an approver for a specified period of time.
So during the absence of original approver, tasks will be delivered to the delegate's inbox.
The original approver automatically takes over after the specified period.
If its not supported OOTB, has anyone implemented it with custom development?

TIA