If your original lease has not yet expired, it is likely still in effect. The change of owners does not normally terminate a lease; instead, the new owner steps into the shoes of the old owner with respect to any existing lease agreements. In general, a month-to-month lease is in effect if you pay your rent monthly and there is no written lease in effect. Under this type of commercial lease, you normally are entitile to 30 days' notice of termination, assuming you are current in payment of the rent, and are not otherwise in breach of your duties as a tenant (ie, you have not caused damage to the premises, you comply with landlord rules, etc.) Verbal notification is technically sufficient, but is alway subject to dispute, so landlords rarely rely on a mere verbal notice.