depends on what the form does.
does the form insert to a database?
Send an email?
you would need to edit the server behavior that processes the form to set a redirect page
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.