I agree wtih Kyle's comments. The SAME lease is still in force. Any changes desired by the lanlord would need to be in writing to the tenants with length of notice as noted in the lease. Not sure, however, if there are only ceratin changes that can be made, or if any changes are ok. If for some reason the landlord doesn't like the current lease, he can terminate the current one with proper notice, and sign a new one with the tenants to be effective after the notice requirement is met. At least that is my perception - but, also, Greg is right - if you want to be doubly sure, ck the property code.
