IHTM45041 - Reduced rate for gifts to charity: elections: procedure
An election to merge components (IHTM45035) or to opt out of the reduced rate (IHTM45040) must be made in writing and delivered to HMRC by the appropriate persons (IHTM45042) and within the time limits (IHTM45043). If the election for either merger or opt out is made before delivery of form IHT400, a separate schedule - IHT430 - can be used. Otherwise, there is no specified form for either election.
Either election can be withdrawn by a notice in writing made by all those entitled to make the election. An officer of HM Revenue & Customs has the discretion to admit a late claim (IHTM45042).