IHTM40147 | Changes after the issue of the clearance certificate: statutory amendments to the estate
From HM Revenue & Customs · Inheritance Tax Manual
A certificate does not stop you from collecting any additional tax that becomes due if the value of the estate changes as a result of any of the following
disclaimer of an interest in settled property (),
variations () and disclaimers (),
compliance with testator’s request (),
distribution from property settled by Will (),
redemption of surviving spouse’s or civil partner’s () life interest on intestacy (), .
This applies irrespective of the title at which the amendment is made. If this view is challenged you should refer the case to Technical.