When you complete an entry form on behalf of someone else, the system creates a profile for them in your Racesignup account. This makes it easier for you when you come to enter that person in another event.
If you no longer want to have this profile in your account you can delete it. Go to Your Account
and log in. You will see a list of the profiles you have saved. Tap on the pencil icon next to the name you want to remove. The edit profile page is displayed. Tap on the Delete button and confirm.