Originally Posted by GUWonder
It's happened before, but I wouldn't necessarily count on it. The best time to do it is when you have some flight history to show UA.
If you have a long flight coming up, it might be best to book it on CO or a CO partner (just be sure to get CO status first). Then you can fax your statement showing thoseYTD miles to UA (and since it's close to the start of the year, not having many YTD miles won't be a problem).