It is not always the case that giving notice amounts to an unambiguous act of resignation, which the employee cannot then change their mind about.
The claimant worked in a hospital’s record department. When she received a conditional offer to move to the radiology department, she sent a letter saying "Please accept one month's notice from the above date". The new offer was withdrawn and she sought to retract her “notice of resignation”, which her employer refused. Her employment ended and she claimed unfair dismissal.
The tribunal held her notice to be ambiguous, not necessarily referable to resignation. The tribunal was entitled to conclude that the hospital had understood the words as merely intending to signify the move between departments and when the new offer was withdrawn, she was entitled to retract her resignation.
East Kent Hospitals University NHS Foundation Trust v Levy