SolvedDANSP52400 | Appeals: Settling appeals by agreement: Decision superseded by further decision
From HM Revenue & Customs · Decisions and appeals for National Insurance Contributions and Statutory Payments
Regulation 11 of the Social Security Contributions (Decisions and Appeals) Regulations 1999 (SI 1999 No 1027)
DANSP52100 explains that appeals can be settled by agreement before being determined by the tribunal and tells you what to do when settling the appeal.
Regulation 11 makes provision for an appeal against a decision to be settled by a superseded decision being issued. See DANSP45600 about superseded decisions.