Global Premier Upgrade with infants can be really expensive
I booked a business saver award flight for my wife in November to Europe. Back then the agent told me that there would be no cost to add my baby. When my baby was born in December, I called back and UA told me that I had to pay 10% of the business fare ($542). Of course now there are no more economoy saver award on this date. I could change the date, but UA will not waive the $250 change fee on the ticket purchased for myself. So I have the choice between paying $542 and keep my business ticket or $250 and downgrade to economy.
My recommendation: Get the agent to confirm in writing, if they tell you that there is no cost to add an infant.
PS: Really disappointed that UA could not waive the change fee given the fact that they had misinformed me.