Is there a way to undo a move when playing live chess

I was playing a 30min game with black pieces  against a guy today and he made an accidental drag and drop mistake.  He wanted to do a king side castle (the board was ready for it) and clicked  the king on e1, but mistakenly clicked on f1 square.  The king moved from e1 to f1 instead of a castle .  I sensed it and asked him to do an undo if he wants.  We were trying to figure out how to do this, since both of us agree on this. But we could not locate the feature? Is there a way to do this?

thanks

No, that is no different than moving the piece to the wrong square in a real game. It happens. 

In a non rated game I think you can (not positive in live, I know in Daily you can) but in a rated live game there is no way. 

what if someone makes a calculation error, says it was a mis-click, and he gets to try again. this feature would be great. but there will be people who'll take advantage of it.   

They definitely should add this feature, like on lichess.

If your opponent asks about take back it's up to you accept or decline