Login to your account on https://laderarec.activityreg.com/

Click on ACCOUNT on the top blue menu bar

Select Family Member for reservation you wish to cancel

Click on FACILITY RESERVATIONS on dark blue menu bar

Select the reservation from the list that you want to cancel.   

Either double click on that reservation or click the light blue VIEW DETAILS button

Click on the red Cancel button, confirm your cancel by clicking on the red button in pop up window.