Maybe what you need to consider is a written contract that has a cancellation rider on it.

Something to the effect that if either party cancels within a certain timeframe before the contract date that half is still owed to the performer. Or whatever deal you think is worth it.

There are plenty of examples of music performance contracts to peruse if you websearch.

Ever since I put that rider in there, it is amazing how GOOD the worst of weather has become to these folks...
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"Keep listening. Never become so self-important that you can't listen to other players. Live cleanly....Do right....You can improve as a player by improving as a person. It's a duty we owe to ourselves." --John Coltrane

"You don't know what you like, you like what you know. In order to know what you like, you have to know everything." --Branford Marsalis