If extending the reservation would overlap with another reservation the request should be denied.
In order to extend the current reservation it may be necessary for the admin to manually push back the start time of a following reservation.
There is a possibility that the input required for the job(s) in a reservation arrive earlier than expected. The admin would like to be able to move the start time of the reservation forward so that the job(s) can start sooner.
If the job is done sooner then expected the admin would like to be able to move the end time of the reservation forward to free up the resources.