[1]. Get a Book & Quill
[2]. Write the player name of the new owner in it (the player must be online)
[3]. [below 1.21.5] While holding the Book & Quill, look at the pet you want to transfer and run /trigger transfer_pet_owner
[3]. [1.21.5+] Sneak + look at the pet you want to transfer with the Book & Quill in your hand
[4]. You're done!
