OK. You don't want your existing PR status any more, correct?
Presumably you are currently outside Canada, correct?
So, to reenter Canada with an expired or lost PR card, you can apply for a PR Travel Document. (As a visa exempt national, you don't actually need it, but you are using the application to trigger a process).
The embassy see that you have failed to meet the residency obligation requirements.
They then formally refuse the application and report you for failing to comply, but give you the option to appeal to keep your PR status.
You ignore the appeal option and by default your PR status is revoked.
You are now back as a foreign national with no status in Canada.