Can I lock a form without using the signature line??

[TWorthley]

I have created a 4 page form with a customized submit button on page 4. the button merely adds to the subject line and msg body along with a specified email address. I need the form to lock, except for the last page. The fourth page needs to be able to change or add additional data.  Is there a way without using the signature field for me to lock the form??

[TWorthley]

Is there any other way to lock a form?? I don't have a signature line, but I need to lock it from others changing any data after I have completed and forwarded on to the next recipient?