So this is where LH and LX despite being the same company can be super frustrating. So I had a missed call from a +49 number and an email with Lufthansa branding saying to call them. So I did. Oh it's a 724 ticket, we can't touch it, but we've remarked the booking so Swiss can rebook you.

Call Swiss, oh, there's nothing we can do, we can see the remarks but as you're confirmed (sector shows HK1) we can't rebook you.

Call Lufthansa, yes, we've been receiving lots of calls about it, they use the same system that we do, they should rebook you as we're doing for our customers.

Call Swiss, no, still can't rebook you, still says Hk1, and yes, I can see availability is going but my hands are tied.

....