How to change the display column on the attach dropdown?

Good afternoon, folks, how are you? Let me ask you a question here. How do I customize which field will be rendered in the dropdown of the attach? In my case, the Model being listed is called Subscription, and it's showing its id. I want it to show Subscription.user.name, which is the id of the user linked to this subscription. Note: the linked id remains the subscription's, however, the label of the option should be the username responsible for this subscription. Did that make it clear?