uncheck

/AH0 N CH EH1 K/
verb
  1. 1

    To remove a checkmark.

    โ€œUncheck the โ€œsave my passwordโ€ box.โ€

  2. 2

    (travel) To remove a previously checked-in passenger from the check-in system, allowing changes to the ticket.

Antonyms

Source: https://en.wiktionary.org/wiki/uncheck