Leave it as it is―Leave it as you found it―(は物、事件なら)―Let the matter rest there―Let the matter drop.
No action is required on your part.
Don't touch that.
Please don't move that.
内緒にしといてね。
内緒にしといてね。
Please don't tell anyone.
それほかしといてや。
Leave it as it is.