Note: OP2 is from 2006. The current procedures listed online are similar though:
https://www.canada.ca/en/immigratio...onomic-classes/family-class-circumstance.html
Switching categories between spouses, common-law partners and conjugal partners
Conjugal partners, common-law partners and spouses are all specific categories with specific requirements. The onus is on the applicant to indicate what their relationship is to the sponsor, to specify the immigration category and to fulfill the requirements of the category under which they apply.
An officer is
not required to automatically re-assess an application based on a different family class marital/conjugal relationship between the applicant and the sponsor than the one identified on the original application.
However, applicants are obliged to
inform the Department of any change in their marital/conjugal status before the finalization of their case. For example, an applicant sponsored as a common-law partner (immigrant category FCC) or conjugal partner (FCE) may marry the sponsor. In such cases, a new undertaking is not necessary, but an officer must continue to be satisfied that the relationship meets legal requirements and is genuine.
If an applicant is refused as a common-law or conjugal partner and subsequently marries the sponsor, there is no provision for the original application to be revisited purely on that basis – if the sponsor and applicant wish to pursue an application, they must re-apply and pay new fees under the appropriate category.