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Is there a 24 hour rule or similar, or can I do it the morning of departure? If the departure time ticks by with me doing nothing, what happens then?
Based on the snippet, this fare appears to allow you to no show and still get a refund, but I wouldn't reach that conclusion without reviewing the entire fare rules. I would be comfortable saying that so long as you cancel before the check-in cut-off (T-60), you will be fine.