Editing fillable fields when I'm not the author of the document

Hello!

I have a document whose fields are all fillable. It's an HR employee change form that, depending on the change, does not require all fields to be filled out, ie when we send form to employee for signature, the employee isn't forced to fill out all the fields; all we need is the date and signature.  

I am looking for a workaround on this. Note that I am not the author of the form so maybe this is the catch?

Any help would be greatly appreciated!