Taking over existing tenants

[Christopher Cannon]

Buying a duplex that already has one lease and one month to month on it. Rent is way below market. How do I go about taking over the leases, acquiring the security deposits that were made, and possibly raising rents as soon as possible. Is there a probation period after purchase to raise rents etc. this would be my first multi family and my first home taking over existing tenants. Thank you