In Washington State there are three ways to identify the signing party (RCW 42.45.050)
1. Identifying documents – The most common method of verifying a signer’s identity is to look at some form of identifying documents. The Washington State notary statutes point out several options for documents that a notary can use to verify a signer’s identity:
• A passport – Out of country ok.
• A driver’s license – Out of state ok.
• A government-issued identification card
Government identification must contain the signature or photograph of the individual and is satisfactory to the notary. A notary can accept any identifying document that is either current, or expired for less than three years.
2. Personal knowledge – If you personally know the signer, you do not need any additional identifying information. The notarial statute (RCW 42.45.050) says that a notarial officer “has personal knowledge of the identity of an individual appearing before the officer if the individual is personally known to the officer through dealings sufficient to provide reasonable certainty that the individual has the identity claimed.” Generally, you can rely on personal knowledge when you have known thee individual a long enough time that you would be willing to swear in court as to who the signer is.
3. Credible witnesses Identifying documents – . This is a more difficult standard, because it requires having a third party involved in the process. In order to use this method, a third-party witness must swear an oath and sign that the signing party to the document is who they say they are. The witness must be credible and personally known to you (see above on personal knowledge), and needs to provide identifying documents (see above on identifying documents) to prove their identity. Finally, both the signer and the witness must appear physically in front of you during the notarial act.
I have the Credible Witness provide ID, sign my logbook, and I complete a Washington Notary Acknowledgement (Credible Witness).
Sample Oath:
Oath: “”Do you (name of credible identifying witness) swear that you personally know (name of document signer), that (he/she) is the person named in this document, that it is your reasonable belief that it would be very difficult or impossible for (him/her) to obtain an I.D. card for purposes of identification, that (he/she) does not possess an acceptable identification document; and that you are not financially involved or named in this document, So help you God?
Affirm: “”Do you (name of credible identifying witness) affirm on your honor that you personally know (name of document signer), that (he/she) is ther person named in this document, that it is your reasonable belief that it would be difficult or impossible for (him/her) to obtain an I.D. card for purposes of identification, that you do not have a financial interest, nor are you named in the document?”
Further reading from National Notary Assocation: Notary Essentials: Using credible identifying witnesses
NOTARIAL SERVICES, ETC 