The link in the email looks like this:
If you don't have the original email, it can be resent to you by following these steps:
1. From the main page, click on the link to have your confirmation email resent to you
2. You'll be presented with a listing of currently active scrimmages. Choose the one that you need to drop:
3. You'll now be presented with a list of players who have confirmed. Choose yourself, enter the Captcha information at the bottom of the page, and click the Submit button
4. Very shortly after, the original confirmation email will be sent to the email address you used to sign up for the scrimmage. Within that email is the link to drop your spot in the scrimmage
The final step in dropping your spot in the scrimmage is to click on the drop link in your confirmation email. Once you do that, you'll be presented with a page confirmation that you dropped your spot that looks like this:
That's it! Your spot will be given to whomever is at the top of the Reserve list!