Same in the US.
You can try voting again at other stations, especially since they don't require ID. You just need the name of somebody assigned to that station, who hasn't already voted. There is a signature check if there is a suspicion, but that's rarely done.
But that's practically never done. The risks are too high, and to have a significant impact would require enough votes to make it certain you'd get caught.
You still need id in Canada; either that or someone at the same polling station to vouch for you.
https://www.elections.ca/content.aspx?section=vot&dir=bkg&do...
The signature check is actually not uncommon, particularly if the vote is contested or a recount done.
We had a vote thrown out of an election several years ago, the woman died right after the election, the signature on the card looked nothing like hers and was probably done by her daughter.
That said all indications are voter fraud is not any kind of wide spread problem in the United States.