Where a person is entitled to an interest in another person's estate ( IHTM04043) and the administration of that estate was not complete by the time the second person died, you may need to quantify the value of the unadministered estate as part of the estate you are looking at. Where inheritance tax was payable in connection with the earlier death you may be able to allow some of that tax as a relief against the tax payable on the second estate. There is a similar relief on lifetime transfers ( IHTM04051) on termination of an interest in possession.