Your reservation is valid for 4 business hours. Check howtobringme.com to find out when your Bringme Box is accessible, i.e. at what time the 4 hours start counting. If your reservation expires, you can go to the Bringme Box during the next 5 days (this is merely an indication because the maximum number of days differs depending on the box) to see if there is an empty compartment. You must then reserve a new compartment.