Regence Blue Cross Blue Shield Utah. General Inquiries. Regence Blue Cross Blue Shield P.O. Box 1388 Lewiston, ID 83501-1388. www.ut.regence.com. Member Services. 1-800-421-4498. ... You will be going to a new website, operated on behalf of the Blue Cross and Blue Shield Service Benefit Plan by a third party. The protection of your privacy will ....