When I go to the restaurant I want to know if Julio is working. He is a friend and a good waiter, so I want him to wait on me.
Is Julio working tonight?
¿Trabaja Julio esta noche?
would be a simple way to express it, even though, explaining that you wish him to be your waiter, would probably be better.
¿Pudiera Julio servirme esta noche?
servir mesa=wait (waiter/waitress) on a table
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