Hi all, I'm flying on JL044 in the new year (London -> Tokyo) and have Crystal status. I chose JAL specifically for the advanced seat selection and paid significantly extra for this flight for this reason as well as others. I managed to get 45K (leg room, window) and almost a month after booking it I received an email today mentioning my seat has "been disrupted" and I am now assigned to 45J. 45K is no longer available, and neither is any other of the seats in this row.

I have reached out asking for a reason but am pretty sure I will not receive one. I have extreme difficulty sleeping on flights and wanted the leg room, window seat and no chance of people waking me up to use the toilet hence this selection. We all have reasons whether or not they are entitled, but in this case I worked towards this status and paid up to get this.

So I'm wondering what my recourse is, if any, here? Is it reasonable to ask them to move me to the same flight on another date where the seat is still available? And is there any valid reason why this seat was re-assigned to someone else?

Thank you!