Multiple Signatures and Modifying Text

I use Adobe Acrobat Pro X on a Mac (10.6.8) and have created a form with two digital signatures.  The form needs to be filled in by the employee at the top and digitally signed, then emailed to a supervisor for his/her signature.  Is there a way to partially prohibit the text from changing in the upper portion (specific fields) above the employees signature after it's been signed by the employee but allow the supervisor to check a box and digitally sign the form too?