No, I am not your lawyer. But the post telling the tenant to change the lock to bar entry by the landlord could be considered giving legal advice.
I simply warn non-attorneys not to render legal advice, the state laws are very strict on this practice.
I often post with disclaimers that laws vary by jurisdiction. I advise consulting an attorney in your jurisdiction and checking with government authorities for the local rules/regulations.
Self help can be dangerous and/or costly.
e.g. You have changed the lock without permission and have not given the super/landlord/agent a working key. You and the family are away for Pesach. Your toilet is leaking damaging the apartment below (or more units). The landlord has to break down your door to get in. Not only will you be liable for his costs to fix/replace entry, but you may have been contributory negligent in the damage to other apartments because entry was delayed. Landlord arrived on scene with key that worked when you let the apartment, now he has to go get tools and or labor to break down the door while the leak continues to cause damage.
My advice always tells to to do the equivalent of “consult your LOR” in this case Locally admitted attorney.