Editing a signed PDF : the infinite loop

Thank you all!

I got the answer in this topic: https://community.adobe.com/t5/acrobat/signed-pdf-how-to-quot-save-a-copy-quot/m-p/10758299#M230223

What happens when you click on Save As Other?

Look at above screenshots 😉

Thank you for your answers but it's not my question.

I don't want to edit a signed PDF, I want to edit a copy of a signed PDF as well as Acrobat offers:

MODIFIED ANSWERS

OR,

The appropriate and ethical Adobe guidance would always be to have the creator of the file provide you with the password to unlock the document and then perform your changes and editing.

Otherwise this topic will turn into a controversial one since you can easily remove these restrictions using the web browser method and refrying the document, then re-add signature fields again after you perform edit text and images (if this is the case).

Another useful way to prevent these lockdowns is to plan a head before creating a form. Create the form with an signature field set to remove all read-only content once it is signed and cleared. This allows other signature fields that were previously signed to retain their valid digital signatures but also  allowing you to Fill and Sign again, select different answers from pulldown menus , date pickers , etc for example.. 

You can't change the security settings of a signed document because the signature is over the bytes in the file, and removing security (unencrypting the file) changes all the encrypted data to unencrypted which would break the signature. You can only change security settings if there are no digital signatures (certifying or individual).