Tell them how you value the relationship, why you've selected THEM instead of just anyone, and give them a little time to think it over.
1234, Main Street
Boston, MA 02123
08 April, 2005
<Recipient Address Goes Here>
I would like your permission to use your name as a reference for <our company, product or service>. Not only are you one of our most valued customers, but also an influential presence in your industry. We'd be honored if you would let us share with others, our experiences with your organization.
Nothing speaks louder than satisfied customers. We're proud of the relationship we've built with you and hope you feel the same. I'll call in a couple of days to make sure this is agreeable to you. We really appreciate the business and support you've given us in the past. Thank you.
encl: <List of enclosed items goes here>