今日、デルタの運賃規則 DRX3APS を確認してたら OTHER DISCOUNTS NOTE- UPGRADING USING WORLDPERKS OR OTHER FREQUENT FLIER PROGRAMS IS PERMITTED FOR FARES BOOKED IN Y OR B CLASS. FOR FARES BOOKED IN OTHER CLASSES SEE WORLDPERKS RULES FOR APPLICABILITY RULES. ~~~~~~~~~~~~~~~ 発効日は 07JAN10 NW思い出して少し泣けた