Some will convert to month to month if you don't give notice of termination. (rocketlawyer.com)
The charges didn't show up into my bank account until 4 months later and they did not give any notice of the charges, and they did not let me dispute them. (sitejabber.com)
First, I'd like to acknowledge that it's still very much appreciated when airlines give notice before making these type of negative changes. (uponarriving.com)