Press Ctrl + Shift + C, when the command box opens, type in 'testingcheatsenabled true'. Hit Enter.
Then, repeat the Ctrl + Shift + C, type in 'Resetsim Firstname Lastname'. Just replace that with the first and last name of the foal, then hit enter again. Alternatively, I believe you can Shift + click on the sim and select reset sim, but I haven't tried that in awhile so don't quote me.