You can't stay at the old location, relocation is a valid reason to change a contract arrangement, you could ask the new owners if they would like you to quote though.
If you can't provide cleaners at the new location then speak with the client, it is best to be upfront about these things, whether your contract runs for a year or three or whatever there will almost on every occasion a clause for EITHER party to give notice. Negotiation with the client is the best way forward I feel.
Fox