Tenant wants a roommate

[David Hald]

I've had a tenant in place since 12/2019, now PM is asking if another tenant can move in (a friend of current tenant, they say).

What should I require legally from this person, apart from his personal details? Separate lease? Separate deposit? Extra rent?

I lowered rent and negotiated with current tenant to secure her, but part of my will to do so was that she was one person with no pets. I feel I should get something from this adjustment to our original lease, especially because it will necessarily mean greater use/mileage on the house.

Is there something else I'm not thinking about? 

Any thoughts would be helpful!

Please help!