Verification audit

Answer: Rules for the certification audits for all ISO standards are the same: there needs to be at least one surveillance audit every 12 months. Verification audits are used only if you failed the Stage 2 audit, and the auditor needs to check whether you have closed a major nonconformity.

The 12 month period should start with the date of the completion of the last audit, but it would be best if you check this information with a certification body.

See also these articles:
- Surveillance visits vs. certification audits https://advisera.com/27001academy/knowledgebase/surveillance-visits-vs-certification-audits/
- Major vs. minor nonconformities in the certific ation audit https://advisera.com/27001academy/blog/2014/06/02/major-vs-minor-nonconformities-in-the-certification-audit/
- ISO 27001 Certification: What’s next after receiving the audit report? https://advisera.com/27001academy/blog/2015/05/18/iso-27001-certification-whats-next-after-receiving-the-audit-report/

This book also explains a lot about the process: Preparing for ISO Certification Audit: A Plain English Guide https://advisera.com/books/preparing-for-iso-certification-audit-plain-english-guide/