Delegation management

Hi ,

We have a Use case on the delegation functionality,Where the user abc will delegate his tasks to xyz for the period of duration(for example:01-08-2019 12 PM to 02-08-2019 12 PM) .this will happen from Angular UI.

I’m trying to search the API in Task engine services reference guide and able to see updateTask will have this.delegatedFromList,delegatedToList But could not able to see any fields available for setting the duration of delegation.Could you please help on this?