You are able to edit or update riders details in the Athletes section of your Horse Monkey account, whether via the Horse Monkey website or via the app, to do this:-
Log in to your Horse Monkey account, then ..
On the website go to the left hand side menu - select Athletes.
On the app, click the 3 lines in the top right hand corner to reveal the menu on the left hand side - select Athletes from there.
You then select either Active Athletes or Archived Athletes.
You will then see a list of all Athletes associated to your account, click the Athletes name you want to edit.
Click the blue box Edit Athlete Profile then scroll down to update the required sections.
Click Update Athlete Profile to complete the process.
The changes will now be saved and will carry through, if it's a requirement, on all future entries.