In the Lufthansa section in the original posts, there is this reference to United Airlines SWUs for upgrading on LH:
Originally Posted by Kiwi Flyer
UA Mileage Plus SWUs can be used to upgrade.
- This upgrade may be used on a standby basis, subject to availability, on the day of travel on any eligible LH flight.
- Valid in all booking classes except when booked in LH booking classes X, I, O, R, N and E.
- This upgrade requires a 14-day advanced notification to MP in order to print and mail the certificate for presentation to LH on the day of departure.
Just FYI, the valid booking classes have changed. W fares are no longer upgradable with an SWU, unfortunately. This
link to United's SWU rules now reads:
1a. Lufthansa Standby: This upgrade may be used on a standby basis, subject to availability, on the day of travel on any eligible Lufthansa flight following in accordance with the terms and conditions of this certificate, except when booked in LH booking classes X, I, O, R, N, W and E. Please note: This upgrade requires a 14-day advanced notification to Mileage Plus in order to print and mail the certificate for presentation to Lufthansa on the day of departure.
(emphasis mine)
Slight, but important, change in terms.
Very useful thread, thanks!