You should be able to just go and try to reschedule any time of day. I went after I missed the date for my drug test 9 days later in the afternoon and the guy at the front desk told me to come back the next morning, he took the letter to someone in the back for about 20 minutes. I couldn't get out of work for my medical and emailed Ms. Robinson to reschedule, she didn't reply, hoping for the best. I have to go back there myself. My list number is in the 700's.