@Lynn1795 A couple of thoughts:
1) Any contract with a manager should be clear as to what happens when the relationship ends. Its not something people typically look at but is essential to avoid you being locked in to a bad provider.
2) Ideally have the listing set up with you as the host and the management company as the co host. This way if you have to move managers then you won't lose all your reviews/bookings.
A good manager will not have a problem with this.......