I am at NEW YORK state . My husband had change the lock of our apartment two days after I left with our son. However the apartment has both of our names in the deans.What Can I do?

First its not a good idea to piggyback your question on someone else's. This can lead to confusion. You should start a new thread. So I've moved your question to its own thread.

Also this is more Family Law instead of Real Estate Law. You say you left. Under what conditions did you leave? Did you tell him you were moving out? Did you tell him you were getting a divorce? We need to know more about the circumstances of your leaving to know whether he was within his rights.