I was trying to get an upgrade in the United.com. Just under my itinerary in "Request an Upgrade", there is a link: "Purchase a 500 miles Upgrade kit" ($325). After my purchase, I learned that it only works for US, Central America and Canada travels. I will go to South America and would need the Economy Plus Year Plan ($349). I called United Airlines and United.com costumer services and they didn't allowed me to change the plan or to cancel the first purchase. All the representatives sent me to other sectors or tried... read full review »