There is a setting under Room Block that allows you to set the earliest checkin date and latest checkout date. If you adjust them, they should flip those boxes to Green. Also take a look at the Allowable Shoulder Dates, those appear as Blue. Normally I keep the main dates of the conference in Green, and then allow 3 days pre/post (if the contract allows it).
------------------------------
Michele Runge
Housing & Registration Manager
HPN GlobalUnited States
------------------------------