Adding infant when seated in E+
 

I have an upcoming transcon booked on the 739 for 2 adults + a lap child using miles. I also paid ~$350 for 2x seats in E+ and no longer have any UA status


Now that the trip is near, I'm reconsidering whether I really want to hold the infant for such a long flight. I was going to purchase a 3rd ticket (using $$) but I would then need to pay an additional $200 for the infant to sit in E+, plus I'm not sure how to add the infant when we're on an award reservation.

Just wanted to check if anyone had any creative options for this situation?

If possible to get the E+ fees refunded, I would be fine with 3 seats in Y-.