Is it permissible for a company to change the clauses of a contract concluded with teachers and give them the choice between accepting the new contract or being dismissed, knowing that the new contract involves harm, risk, and coercion?

If the contract is for a fixed term and has expired, then each party has the right to demand a change in its terms or its cancellation. However, if the term has not ended, the contract is binding on both parties, and fulfilling its conditions is obligatory. The aggrieved party has the right to rescind the contract if the other party breaches it or alters its terms without their consent. If they agree to continue, then they are bound to fulfill what they have accepted.