Get back Garages from Tenants

[Arby Gharibian]

I have a triplex and I'm planning to build a unit on top of my 3 car garage. This requires to demolish and rebuild the garage. Currently I have 3 tenants that utilize the garage and basically it's theirs, we put it in the contract (each tenant has one garage). What is the best way to ask them to remove their belongings from garage and not use it for 8 months until I rebuild the garage and give it back to them.