Definition - What does Ademption mean?
Ademption is the act of bequeathing something in a will to someone and then selling it, giving it away or having it destroyed prior to the execution of the will. This would not have to be done intentionally; it could be due to an accidental fire or the need to sell assets to survive while still alive.
The effect of which is that a person does not receive the asset left to them in a will because it is not available for transfer.
Justipedia explains Ademption
The will writer would always have the ability to do with their assets whatever they want, so they could write a will in the event that any property is left after their death, but they would not be required to make sure that the asset was available to be bequathed when they die.