Well, I'm doing my first MR on Wednesday morning, YHZ-YYZ-(YEG-DEN-LAX) (bracketed portion on Skywest/UA codeshares). My question is, what happens if one of my flights are cancelled or I miss one of my flights due to weather-related delays (I ask because I've never had a flight booked that was cancelled). If my first flight is cancelled, will I be able to book an alternate itinerary without additional charges, or will I have to book an entirely new itinerary as if I were booking for the first time?

Also, if I miss one of my flights due to weather-related delays or cancellations, it is my understanding that AC will find me a seat on a plane going to my final destination, via any routing possible. Is this true?

If this occurs, and AC reroutes my travel, is there any way I can receive miles for my originally booked itinerary, or will I be left with the miles I've flown?

I'm interested in hearing your thoughts on this scenario, particularly if you've been in a situation similar to the one I am describing. Thanks!