NIM30010 | Special Cases: Married Women: Cancelling an election: General
From HM Revenue & Customs · National Insurance Manual
Regulations 127-8, Social Security (Contributions) Regulations 2001
A woman who wants to cancel her election and pay full rate Class 1 contributions or Class 2 contributions must:
complete form CF9 (application for a certificate of election of reduced rate liability or to change to full liability) which is available on GOV.UK; and
sign the declaration at ‘A’; and
if working for an employer, ask them for her certificate of election; and
send form CF9 and the certificate of election to National Insurance contributions and Employers Office, HM Revenue and Customs, BX9 1AN.