Originally Posted by
dodgeflyer
Bumping an older thread but is LH willing to accept an SWU on a flight where you are already booked into I?..
No that is clearly against the rules (I assume you have a Y ticket and hold an ug to I with eVouchers or LH/UA miles): confirmed instruments cannot be swapped for standby ones in the DM window.
That does not mean that it would not work. Especially in places which are populated with clueless agents. I was able to do this in BKK e.g.