How can I change the message for the ticket confirmation?

I clone my forms and I am getting a lot of emails from people who are confused because it sends a ticket confirmation message from a previous event. How do I change this?

What you can do is to manually edit the email template: https://www.jotform.com/help/430-How-to-Edit-the-Email-Template-for-Notifications-and-Autoresponders

Or, delete it to create a new one, which will be updated with your existing form fields.