Rule 903 Subscribing Witness' Testimony Unnecessary

If someone signs a document as a witness, you do not need to bring that person to court to prove the document is real. Other ways of showing the document is genuine are perfectly acceptable.

There is one exception. If the laws of a specific place (like another state or country) require a signing witness to testify in order for that document to be legally valid, then you would need to follow those rules instead.