I just wanted to share my experience with my attempts to change an award booking which had a lap infant attached.

Here's what happened to me yesterday:

if you attempt to make any change online, the system will double charge you miles. In my case the original booking cost 120k miles plus a 600 dollar lap infant ticket fee on a rt saver award in business. Changing the date of the return flight to the next day, which also had saver availability increased the cost to 240k. I didn't have the additional 120k in my account, so the system wanted over 4000 dollars for the miles.

This was obviously some kind of mistake so I called in to the reservations desk and their computer was spitting out the same result-- another 120k. Representative couldn't figure out what was wrong and put me on hold for about 45 minutes while he consulted his supervisor and the rate desk.

After the wait, the rep came back to me and said it's going to take a lot of work, but we can change your date to the next day you requested, but its gonna cost me another 500 dollars because the fare had changed. I told him, that cannot possibly be right, because 1100 dollars total for a lap infant on a simple round trip flight, would presume a full fare of 11000 dollars. he stuck to his guns and said its 11000 dollars.

At this point, i just figured arguing is not going to help in this circumstance, because the rep was already frustrated with being on the call with me for 45 minutes now, so i figured the only way to fix the problem was to just blow up the whole reservation by removing the lap infant from the ticket entirely. (i was guessing the reason why the computers were not handling the changes properly was because of the infant).

The process of removing a lap infant took another half an hour because apparently they have to create a dummy booking to move the lap infant to, then cancel the dummy booking and then refund from the dummy booking. (i am still hoping nothing went wrong with the refund and i get my money back)

After all that i was able to modify the flight myself online without being double charged. I called United again after that, and said i wanted to add an infant to the ticket and was charged the appropriate 600 dollar instead of the 1100 which i paid.

Assuming the infant gets properly attached to the ticket, and my original refund comes through-- the moral of the story is do not add an infant to a ticket until you are certain you will not need to make any changes to your reservation

I just wanted to share my data point with other parents considering a lap infant booking before the devaluation hits.

Perhaps another moral is not travel with lap infants but i will redact that so as not to start a flame war.

moral was: not add an infant to an award ticket until you are certain about not changing dates of flights