Again, it's on a case-by-case basis. For example, if someone says, “I'd like to bring my vehicle in for three months,” and something happens and three months become four months, they can simply contact Transport Canada and say, “My permit number is such and such, I had stated three months, but I need a little bit longer.” As long as it's for a valid reason, the permit is extended.
On May 9th, 2019. See this statement in context.