If you're applying inland, include an extension application with the "initial work permit" option checked. As long as the PR application and the extension application (plus all applicable fees) are received by CPC-Vegreville BEFORE your current status expires, you have "implied status" to remain in Canada and continue under the conditions of your original entry. If you hold a work permit, you can continue working for the same employer in the same position until first stage approval is granted and you receive your open work permit. Then you can go to work anywhere.
Section 5.22 of the
Foreign Worker's Manual talks about this:
5.22 Work without a work permit R186(u)—Implied status
R186(u) allows for persons to continue working under the conditions of an expired work permit, as long as they applied for a new work permit before the original work permit expired and have remained in Canada. Once the decision has been made, the client will either have to leave Canada or will continue as a worker who holds a valid work permit.
Part II of the
Inland Applicants Guide explains about including the extension application WITH the PR ap to protect temporary status. Be sure that you track delivery of the applications and get signature confirmation of receipt. Then you have proof that you're entitled to continue working under your current permit and SIN, even though the dates are expired.