formite

If one of my middle segments of my whole itinerary is through ORD and due to weather issue in ORD, I was re-routed before I even reach ORD, can I get my original EQM/EQS?

How should I do it, fax vs. email vs. call?
Would it change my chance of getting original EQM/EQS if the re-route is initiated by me vs. by the GA?

Thanks in advance for suggestions.