Remove a costume from a convention

[himenomau84]

How do I remove a costume from a convention? I thought I was going as one type but changed my mind. I need to take Otakon 2012 off my Schoolgirl Haruhi.

http://www.acparadise.com/acp/display.php?c=57614

[waynekaa]

http://www.acparadise.com/acp/tools.php?t=costume&v=1
Click the name of the costume
Then scroll down to the bottom and hit the red "x" next to the convention you want to remove