Allow "Request on Behalf of" group/user to edit the request

I submitted a request on behalf of a user/department within my organization. The user can see the request, however, they cannot edit the request as I was the one who submitted the request. If changes or updates are needed to the request, the user has to email me and I need to edit the request. I'd like to be able to submit a request on behalf of a user, but then allow them to edit the request as if they submitted it. This would be helpful for internal facilities requests when someone is out of the office but the request needs to be submitted so the space is reserved.