I've got a Tamawalkie, and I'm really sorry I didn't answer yesterday, when I saw this topic, but I've got problems with my tamatalk loading, and the topic wouldn't load.
I had a similair topic about this a few months ago, when my own walkie was new, and I even put up a video on youtube for when I got it to change back. It evolves into a v5/familitchi large family member if you overfeed it snacks. It does not neccesarily have to be a lot of snacks, but different snacks fill a different amount of hearts. So, basicly you have just to over-fill the hearts for it to evolve into a lage tama. If you don't feed it any snacks, it will become a small family tama, and if you don't feed any food it will turn into gozarutchi. To turn them back you have to feed them a special sort of food or snack.
Meals for turning back evolved tamawalkies:
Large tama + healthy drink = normal
Gozarutchi + energy drink = normal
Small tama + steak = back to normal
HERE'S my youtube video when changing it back anyway.
Good luck and I hope it works out for you!
~lolokotchi
~