What's the English verb/phrase for going back on action when playing chess?

Solution 1:

I've seen takeback used to describe this action of taking back a move in Chess.

Definition on Wiktionary:

Noun

takeback (plural takebacks)

1. The act of taking back or reclaiming anything
2. (chess) The withdrawal of the previous move, as in practice games.

I've also seen Takeback Game used to describe a game of Chess where takebacks are allowed acording to the rules.

For more examples, you can check out the usage of this word on the Chess Stack Exchange site.

Another word that might work here to describe your friend's action can be undid or undo.

Solution 2:

Renege is often used if a single move is taken back.

From MW

transitive verb

: deny, renounce

intransitive verb

1 obsolete : to make a denial

2 : revoke

3 : to go back on a promise or commitment

Other sources, including Wiktionary include:

In a card game, to break one's commitment to follow suit when capable.

I've seen it used in other games, including chess, when a person makes (or attempts to make) a move discovered to be illegal.

Solution 3:

Once his hand leaves the piece he isn't allowed to "take-back" the move. I've also played by the rule that once you touch a piece, you must move that piece, and once you let it go, that player's turn has ended.