Inherited Tenant on M2M

[Brad Birdsell]

I've recently closed on a property in Texas w/ an existing tenant in place. The initial lease term expired and converted to a M2M.  I would like to keep the tenant M2M.  

Is it best to ride out the previous lease agreement established by the former owner/landlord, continuing monthly, or should I establish a new month to month lease reflecting myself as new owner?  If the latter, any recommendations on a source for a solid month to month lease document?

Thanks in advance!