I believe this has been handled in previous posts.
Choreography would in most cases be a "work for hire", meaning that once the skater has paid for the choreography, the skater can use the program as he or she sees fit. Mariah continued to use Rohene Ward's programs in her first year with Raf (she also had Rohene sit with her in the KnC). When Tomoki Hiwatashi left Kori Ade before the season end (I forget the year), he continued to use Rohene's programs. No choreographer cares if you "leave"; they care if you perform their program well and as they envisioned.
And, off topic, as far as I'm concerned both those skaters should have had Rohene choreo after that.
I don't know Alysa's father and I have no idea who did or did not make the decision about a new SP. To me that is irrelevant. It is an unusual decision if it is a brand new SP is developed two weeks before Nats, but we will see if it works for her.