Originally Posted by
PiperAtGatesofDawn
Welcome to FT.
If you decide to book through UA. You can call up UA - give them the UA PNR and get the LH PNR. Then you can use the LH PNR to book your seat on the LH website.
Not if United books the flight as a UA codeshare (LH metal with UA flight number). LH doesn't allow pre-selected seats on codeshares, even in paid first or business class. You can only select seats on codeshares during Online Check-in or at the airport.
Originally Posted by
PiperAtGatesofDawn
Mileage benefits... what the previous 2 posters said. If you're based in the US and looking to build status then PQD could be important to you. If it isn't then LH could be the better option in this case. Although you would want to consider your over travel plans and goals and not decide on mileage earnings for a single trip. That strategy would lead to having a bunch of orphan miles across different programs.
The OP isn't comparing crediting between two (or more) different programs that I could see. Pretty sure they are crediting to Mileage Plus but debating the pros and cons of booking the flights via United vs. Lufthansa. All of the advice I gave pertains specifically to crediting to Mileage Plus, so does the other poster's advice regarding PQD's which I had forgotten about since I'm not US based. Orphaned miles by crediting to various programs is pretty far off base for what's been discussed in the thread so far, no one has talked about potentially crediting to Miles & More.