Seller put tenants Under new lease with lower rents.

[Cary Keith]

Closed today on forth duplex. Super excited but the seller kind of frustrated me. The tenants where paying month to month. One side was rented for $650 the other side $700 with a pet. When COVID started the former owner lowered the rent to $550 each side. I had planned on taking rents back to original price before Covid. After closing the seller informs me he signed a one year lease with tenants at the first of the month for $550.00 on each side. This was after I had it under contract to buy. I thought this was not cool. They are located in Kentucky. I was excited to get this property as good deal are hard to find in my area. Question is can I raise the rent or do I have to wait till end of lease agreement one year from now? Thanks for your help.