Can you reboil an egg if it is not done?

It is not recommended to reboil an egg if it is not done. When you boil an egg, the heat causes the proteins in the egg white and yolk to coagulate and solidify. Boiling an egg again after it has already been cooked can cause the proteins to overcook and become tough and rubbery. It may affect the flavour, color, and consistency of the cooked eggs.

If you find that the first time your egg was not boiled the way you desired, it's always a good idea to start a fresh cooking procedure or experiment more carefully with the correct boiling duration based on a recipe or cooking advice rather than reboiling the partial result again and again.