You don't need to do anything other than maybe keep a record that it was sold.
The State of Utah does not store the gun sale records. It only checks your eligibility to purchase the gun. If you've heard the gun dealer talk on the phone to BCI, you'll recall that they never say anything about the gun.
From what I understand, the gun dealer keeps the transaction records. If law enforcement should ever contact you about it (rare instance) all you have to say is that you sold it. You don't even have to tell them to whom it was sold.
Now having said the above, if the police were to contact you about it, it would be because they were investigating a crime. In that case, I would want to have as much information as I could on hand. I wouldn't freely divulge this information though. Just keep it available should there be great need.
Sent from the Outer Limits via Android.