Inherited Tenants - How to begin a new lease?

[Jared P Walsh]

Hi, I am soon going to be closing on my first property and I will have an inherited tenant while owner-occupying the other unit. Her lease is month to month currently and is 750/month. I want to raise it to 850 because that is far too low in the state of Massachusetts for a 2 bedroom. How do I go about setting a new lease up? Do I need to cancel the existing month-to-month lease and then create a new one?