Rent increase to market, New Owner

[Linzey Ledesma]

Hello BP Family,

I officially closed escrow on my first duplex in Redlands Ca. I inherited tenants. One of them has been renting for 25 years and pays $800 month (market rent is around 1,200). The tenant is month-month (there is no actual rental agreement in place, just an estoppel that seller sent). My question is: can I renew or create a new rental agreement asking for market rent? If they disagree with the new rent then, can I terminate tenancy?

Any advice or recommendations would be appreciated.

Many thanks!