Can an apartment lease be renewed without a signature?

As you know a signed lease is a contract between you and the landlord and unless you are lucky enough to have an understanding landlord and you have a very, very good reason to break this contract then you are responsible for the agreement in that contract. Usually people have to pay the first and last months rent and possibly a damage deposit and you may lose that. You have tied up the landlord from renting to someone else, so it would be to your best interest to offer to let him/her keep the first months rent. Talk to the new landlord and hopefully your reasons for not moving in are valid and you just haven't found a better place to move too. You may just get lucky.