I was thinking to book a trip to Japan in PE as a holiday with BAH, and then use a Joker to open up CW availability to upgrade with a GUF.
I've never done it before, so my doubt is: if I book the BAH trip online, who should I then call to apply the Joker + GUF? BAH or the GGL line?
Also, if the SH flight is operated by EI, there are no issues upgrading just the LH legs, right?