<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by UNITED959:
If your itinerary has 1 or more segments that are not UA/UAX metal, it won't allow you to view the "change" option. 
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Mine are all UA metal flights, and still will not allow me to view the change option. They were all booked by phone tho, not on website.