You have whatever rights your contract with the charter school says you have. You may also wish to review the bylaws of the charter school (which ought to describe how members of the board are selected / elected). If the charter school is owned by a publicly traded company you could purchase voting stock and gain aditional rights.
You of course, also have the right to withdraw your child at the end of the school year and enroll him elsewhere.
This exemplifies the other edge of the double edge sword that is the world of charter schools. They, being private and outside the public school system, are subject to minimal oversight and are not answerable to the public in the same way as an elected school board. They answer to their owners.
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