How to reset google play achievement in blueprint?
if not possible, any clue to do this in c++ (but i want to avoid c++, so i can package game for ios too) ?
You can not reset any achievements if you have released them on your Google developer console. As long as you keep them unpublished you can reset them from within the Google play developers console.
Once you have published them there’s no turning back and you can’t alter them anymore nor can you reset them
Hey 
i didnt found the option to reset them (they arent published yet), where is this option on google play?
Hi and sorry for my late response
In your Google developers console go to the tab [GAMESERVICES] → then your project → then click on one of the achievements.
Scroll all the way down on the achievements screen that opens (where you actually write your achievement and gave it an image) there will be 2 options [Delete achievement] and [Reset Achievement Progress]
I’m translating this from my Dutch control panel to English but I think it should be more clear now.
Again this can only be done if your achievment is in the (Ready For Publish / Ready To Publish - thus testing state)