Yes, if you applied for a permit extension/change before your original permit expired, you can continue working under the same conditions as your original permit while your new application is being processed.
If you have an open work permit, you can change employers. However, if you're applying for a study permit or visitor record, you must stop working when your original permit expires.
To prove your eligibility to your employer, online applicants can show a work permit extension letter, while paper applicants can provide a copy of their application, proof of fee payment, and tracking information.
