It is sometimes necessary for one individual to sign as a representative for another, usually as attorney in fact or guardian, or as a representative of a legal entity, such as a corporation, partnership or trust. Documents signed in a representative capacity generally require special acknowledgment certificates that specify who or what is being represented. Depending on state law or the wording of the particular acknowledgment certificate, the Notary may or may not be required to verify the signer’s representative status. Some states do not give Notaries the authority to investigate and certify a person’s representative capacity, including the state of California. Determining a signer’s authority to sign in a particular representative capacity may be done in several ways: through personal knowledge, by documentary proof or by vouching under the oath or affirmation of the signer or a credible witness. As mentioned, some states do not permit a Notary to determine a signer’s representative capacity in this way. Nonetheless, if you live in one of these states, you may encounter certificates from out of state that require such proof. Completing these certificates may legally obligate you to verify that a signer is empowered to act as described in the certificate. Always use notarial certificates authorized by your own state.