Changing Room Preferance?

Hi!

I recently submitted my housing application, but now want to adjust my preferences. For some reason, I cannot change my first preference, but I can change my second and third. I try to unselect the first preference, but everything is greyed out.

Am I missing something obvious? I feel very stupid…

Thank you!

Oh, also, I am not trying to change halls, just the certain room. I selected Hullabaloo Two-Person Suite, but would like the Single instead. Thanks:)