Is there a way to update/edit the Thanks page that Paypal forwards you back to once you have paid for an event?

We have the event made and signups are working, but once a user pays though paypal, and then after the payment is completed, paypal gives you you a button that forwards you back to our site for a /signup_pay/thanks page and that page has the wrong event name on it. Any ideas on how to change it? (there isn't an edit button like the other pages)