After somebody has died it is possible to make a Deed of Variation that changes the terms and conditions of the will. You will, however need the consent of all the beneficiaries to do this, even if their legacy is unaffected by the changes. My parents made a Deed of Variation after my sister died intestate which meant everything she left would legally go to them, they wanted her estate to go their surviving children without the danger of tax being due if they died within seven years (they were in their late 70s). My mother did die six years later.
After my father died my surviving sister and I used a Deed of Variation to channel part of his estate direct to his grandchildren and also to revoke a puzzling codicil that made sorting out the contents of the house difficult. It wasnt expensive.
🦞 Locked down no longer but still firm friends 🦞