sec assessment in calgary, canada at an earlier date?

Hi,
I want an earlier date for my sec assessment here in Calgary. I was in fact scheduled to give my assessment in April 2013. The coordinator said I will get an earlier date if anyone cancels the assessment. I want to know how often does people cancels or postpone the assessment? Do I stand a chance for getting an earlier date at all?
If anyone has any idea regarding the same, please do let me know. Will be great!!!!
Good day to everyone!!!!