How is the Canadian constitution amended?

Answer 1

For a few types of constitutional amendments that relate only to the administration of the Parliament of Canada (for example, a constitutional amendment to revoke a certain type of parliamentary privilege), the Parliament of Canada can enact the change without any provincial involvement. (The Senate has an absolute veto over any such constitutional amendments.)

For most types of constitutional amendments, the Senate and Commons pass the amendment, and seven out of ten provincial legislatures (for provinces that represent at least 50% of the population of the provinces at the time) must pass resolutions that agree to the amendment. (The Senate can only block such a constitutional amendment for up to one hundred eighty days, should the Commons and provincial legislatures agree.)

For some types of constitutional amendments that make changes to key institutions (for example, changes to the Queen, the Governor General, or the Lieutenant Governors), the amendment must not only be passed by the Senate and Commons, but all ten of the provincial legislatures. The refusal of the amendment by any one of the provinces would defeat the constitutional amendment. (The Senate can only block such an amendment, as above, for one hundred eighty days.)