Hello,
I plan on taking the LTD EXP Hashidate between Kyoto and Amanohashidate. I know that there is a surcharge since the track between fukuchiyama and Amanohashidate are not own by JR. I was wondering to buy a reserved seat ticket between Kyoto and Amanohashidate, can I just purchase it at any JR seat reservation office and pay the difference? Or do I have to buy it at only certain locations?