I just wanted to write this letter to tell you how much we appreciated you and your counsel in helping us to deal with our recent problem.
Your knowledge and experience helped us to understand and deal with our complicated situation. You helped make a difficult situation proceed smoothly. The outcome was better than we expected.
You're one of those few professionals that we would unequivocally recommend as someone who would do the upmost for their client. Please feel free to use this letter as a referral.