I still don't get it. Does the new Vegas affiliate intend to stay in San Antonio? Who owns the building where the Rampage previously played? Does Spurs Sports & Entertainment have a lease for a certain number of nights for the year? Who pays the lease payments going forward? ...
(1) VGK has publicly indicated they intend to move the AHL franchise they are buying (which is a transferrable asset related to but separate from the team now playing in San Antonio) to the Las Vegas, Nevada area.
(2) Bexar County, TX (and by extension their taxpayers) own the AT&T Center in San Antonio.
(3) Spurs Sports & Entertainment L.L.C. (SS&E) operates the AT&T Center under contract to Bexar County, with responsibilities that presumably include securing leases & filling calendar dates in the arena operation (typical duties of an arena management company). I don't know the details of their contractual agreement with Brexar County, but those details could be matters of public record for those sufficiently curious to seek them out.
(4) Per (3) above, it is the responsibility of SS&E to find one or more new or existing lessees to fill the dates to be vacated by the AHL franchise departure to the extent required by their arena management contract. Or whatever other options SS&E have available to exercise in accordance with their contract.
ETA: I see you & others answered your questions already. So never mind.