question regarding inherited tenants with lease agreement

[Annie Rao]

we are buying a rental property. the rental property has been managed by PM. we decided to not use PM after closing due to negative cash flow. the closing is in couple days. I just signed assignment of rent, deposit and leases from PM. I also got lease agreement for existing tenants. My question is should I sign a new lease agreement with existing tenants after closing since the existing lease inherited from PM is singed between tenants, seller and PM. Just want to make sure this inherited lease is legally valid.