How do I make it so that the other person can't see an old text that I sent to them on imessage?

I texted a rude message to someone three years ago. They didn't have my number, so it just showed up as my number with no name attached. Now I need to call this person, but I don't want them to see that I texted them that. Once I call them and they know it is my number, they will be able to go back and see that I texted that to them.