If so, the polite thing to do is notify those next on the list. Be very careful in not spreading disease from farm to farm. Shearers are paid on a per head basis. Treat the sheep well. If a shearer does not live up to expectations, make a note not to hire him again.
Most shearers are good people and work hard.
Make sure you communicate your expectations to him. Summary Good shearers can be hard to find. Especially, if you have a small flock. You may have to be a bit creative in contracting the services of a shearer. They will likely be willing to return to shear for you again.