Can my employer elect to move me from Hourly to Salary without my consent?

Calfiornia is an at-will employment state (unless you belong to a union or have a written contract that provides otherwise) and you can be fired for a reson or for no reason. You cannot be fired for belonging to a protected class, e.g. race, religion, etc. If you can be fired, you can be changed from hourly to salary and if you don't like it you can quit or be fired.