Without an old enough earlier save, using the in-game editor one solution is to move yourself to another club in another league the day before the switch happens, remove and re-add the leagues from there, and then move yourself back to your original team a day later.
Mass Retirement of Players and Staff
in Transfers, Contracts, Scouting, Recruitment Meetings and Staff Responsibilities
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Without an old enough earlier save, using the in-game editor one solution is to move yourself to another club in another league the day before the switch happens, remove and re-add the leagues from there, and then move yourself back to your original team a day later.