Originally Posted by
windowontheAside
Its got to be worth checking. The alternative is to buy a separate ticket and baggage allowance which may not be cheap. Add the necessary wait time and misconduct risk, plus the inconvenience of stopping and paying change fees & fare difference might start to look attractive.
Plus of course, changing the tix would mean the pax would be in J all the way rather than have the 6h transcon in Y on UA per option 1.
Also worth mentioning that the direct LHR-SFO wouldn't be the only option. For example there may not be I class available on the direct flights but may be on e.g. LHR-JFK-SFO in which case fare difference may (or may not) be small.