Join Date: Aug 2011
Location: Barcelona, London, on a plane
Programs: IB+ Gold, TK E+, Hyatt Globalist, Marriott LTP, IHG Diamond
Posts: 14,186
I don't have a good feeling about TK's IT being able to upgrade tickets including a lap infant.
I have an even worse feeling about TK successfully splitting PNRs and then upgrading just the one adult with an infant attached.
This is especially true given that you only appear to be upgrading one leg.