Word "The" in a sentence

Hello SIr/Madam,

I have a dicussion with one of my colleague regarding a sentence where according to me you can't say the word "The".

The sentence was:

"I want to Rent the downstairs.", accoring to me that's incorrect and can only be used if you add a word like room or partition. i.e. "I want to rent the room Downstairs.". Can you please let me know if sentence can be used in a normal day to day life?

A: "I want to Rent the downstairs."

B:"I want to rent the room Downstairs.".

Thanks in advanced.

Nick