If your passport is lost after receiving your ITA and submitting your Canadian Experience Class (CEC) application, this is a fixable, fairly common situation:
- File a police report for the lost passport first. This is typically required to apply for a replacement passport, and it also gives you documentation to explain the situation to IRCC if asked.
- Apply for and obtain your new passport through your country's passport authority.
- Inform IRCC of your new passport details via web form once issued, so your application reflects your current, valid travel document.
Keep the police report on hand even after getting your new passport — it's useful proof if IRCC has any follow-up questions about the passport change during processing.