Try r/immigration
Most people here are US citizens and don’t have experience with needing visas. But if the question is just what to tell the airline - tell them you have a visa
surely you will be leaving on a UK passport to the UK. Why would they care on the outbound what visa you have? We switched our visas from L1b to L1a i think back maybe 10 years ago, may have been the other way around. our original visa was going to expire due to time limit of 5 years i think, hadnt expired though. Once paperwork was done we drove to Toronto, nearest immigration office to us outside of US, submitted our paperwork and then just had to wait, stayed in a hotel until we got the call, went back for the stamp and had no problem entering. I’m not sure how they granted a new visa without forcing you to leave, we had to leave to finalize it all.
Try r/immigration Most people here are US citizens and don’t have experience with needing visas. But if the question is just what to tell the airline - tell them you have a visa
surely you will be leaving on a UK passport to the UK. Why would they care on the outbound what visa you have? We switched our visas from L1b to L1a i think back maybe 10 years ago, may have been the other way around. our original visa was going to expire due to time limit of 5 years i think, hadnt expired though. Once paperwork was done we drove to Toronto, nearest immigration office to us outside of US, submitted our paperwork and then just had to wait, stayed in a hotel until we got the call, went back for the stamp and had no problem entering. I’m not sure how they granted a new visa without forcing you to leave, we had to leave to finalize it all.
Question for ukvisa. Removed.