The document is probably locked since you say it was signed by Adobe and therefore cannot be manipulated/imported.

Hi.

If you were able to modify a signed pdf this would be a security issue. There are programs that will allow you to do that, but they will track changes made after the documents was signed. Also the signature will show you a warning. You have to think how pdf with fields would work. Let say I have a pdf to be signed by two persons. Each one has to fill some fields and then sign. That can be done concurrently. Person (1) fill the appropriate fields and sign the pdf. Person (2) get the pdf, then fills the appropriate fields and sign it. It is possible to check what was the state of the pdf when it was signed by person 1, even after an additional signature was added. Also it is possible to check if something was altered after both persons signed. The last is really important...

As you may understand, a signed document should always indicate and validate it's state based on the signature(s). So the best way to get rid of the signature is to print it. Even in that case, modifications that you could do to your document may be limited. Finally, based on the area you live on, there may be danger of legal implications if altering a signed document.

Finally, I haven't seen any software that offers functionality to remove a signature. Word may be able to convert a signed pdf to a docx, but the result may not be identical to the original file.

Andreas.