erusa

Hi everyone,

I booked a multi-stop business-class flight on the LH website.
All the legs are either D or Z class.
The longest legs are HND - FRA and back, operated by NH.

I was planning to upgrade one of those long legs to first class using my M&M miles, but I just found out that codeshare upgrades are not possible on *A...

I read here on the forums that one could try to get the ticket changed (or reissued?) with a different code, in my case NH code.
I called LH in both Germany and Japan, but they thought I'm crazy when I asked them if it's possible to change the code of the ticket to NH.

So I have some questions:
Is it possible to change from LH to NH on one leg or all legs of the ticket, and if yes, how?
Would this give me the ability to upgrade the flight (given that there's availability)?
If it's not possible, is there any other way to get that upgrade?

Thank you!