Yes, Mr. Guimond, there was a case in 1926 which is well known by political scientists. That is when Governor General Lord Bing refused the request of Prime Minister Mackenzie King to dissolve Parliament and to call general elections. The Prime Minister had to call on the leader of the Opposition, Mr. Meighen, to form a new government.
There has been a lot of controversy about that. Even experts cannot agree on whether the consequence was to reinforce the powers of the Governor General or whether it reinforced the notion that the Governor General should not do that kind of thing, that is to say to act against the advice of the Prime Minister.