My mother had an insurance rental from an Enterprise Local Edition in Concord, NC. It developed a flat one a Saturday evening after the Local Enterprises had closed and most tire shops as well. With the donut spare on, it was driven to Enterprise at CLT. A most unhelpful employee who claimed there to be no manager on duty and to be the ranking attendant stated that even though it was an Enterprise Rental, they could not/would not exchange it, that a donut was safe to drive on for any amount of milles, that it could be exchanged the following Monday at the renting location (this was a nearly brand new '13 Charger, so certainly not a beater car they wouldn't have wanted), and then proceeded to fly me the bird (yes, she gave me the middle finger).

After driving over to National/Alamo to see if they could exchange it, two very friendly and helpful agents (one being the MOD) apologized and stated that they could not pull up an Enterprise reservation nor modify it on their computers. So at least per my experience the answer is no it cannot.

P.S. to finish out the story, the manager from National/Alamo contacted Enterprise, personally escorted us back over, had us meet with the actual manager (who was much friendlier), and had us on our way even though they reassigned a '12 Altima that was in piss poor condition.