I avoid ORD that time of year due to the weather. Not much you can do if EY can't get you to the US as scheduled, though unless there is another EY flight after that one. Except to try to talk the next domestic carrier into a ticket change that is not too expensive (it is usually not the change fee that gets you, it is the cost of the last minute ticket you may be changing to - if you are flexible, you may be able to find a flight to change to that is not too expensive; UA.com is good about allowing you to search online for such changes).