If you applied online, once your application has been approved for further processing, you'll be prompted to reply back and eventually you'll be scheduled for the CFAT. You'll then be emailed a bunch of documents that you have to fill out and bring with you on the day of CFAT. You'll get a chance to fill out your personal info and trade choice(s) all over again, where you can correct the error. The only thing is I don't know if the CF approves for further processing based on gender needs as well.