Keep relevant history and identify which terms are now operative. A clear explanation of the change is more useful than presenting inconsistent documents without context.
Make the current arrangement traceable
Record the actual employer, duties, compensation and intended period. Explain material differences between the old and new versions. The support letter should describe the genuine revised job, not silently combine favourable details from both.
The Accountant entry accepts a professional designation in place of a degree, so the strongest file for a designated applicant is the CPA certificate, a good-standing letter dated within the last few months, and evidence that the designation is current rather than lapsed. Gather the share register or shareholder agreement for every company you hold an interest in, the proposed engagement or offer letter, and any document describing how the two companies relate to each other. If the recruiter drafts a letter saying the position is contingent on licensure, ask for it to be reissued once the licence is granted, because a contingent offer invites the officer to ask whether employment really exists. Once the letter is right, the supporting documents simply corroborate it: proof of Canadian citizenship, the degree with a transcript, the provincial licence in good standing, and evidence of any experience the profession's rule requires.