Commercial lease: tenant wants to leave

[Cory St. Esprit]

I own a commercial space that currently has a thrift store in it. They’re an arm of a local non profit. Good tenants. Always pay on time. Their business has grown and they want to leave to find a big space. They have 3 years left on the lease. My attorney has reviewed the lease (I inherited it when I bought the building and we did a lease assumption). There’s no clause to break early - meaning unless I let them go, they’re stuck. I own 28 Subway franchises and would like to move a Subway to the space but it’ll take a year to get it built. 

Bought a on asking tenant to pay a 6 month buyout clause (January to June 2024) just to vacate space by 12/21/23?