Air China Phoenix launched between Hong Kong airlines companion ticket exchange the exchange offer at half price,
Because of limited air operations, but also flights,
So not much can change flights only/Beijing/Chongqing/Chengdu, Tianjin and Dalian
A case study of Chengdu, 22500 miles will earn after the half price ticket, 218 RMB tax paid by another.
Flights and another special date limit:
Hong Kong to mainland China on May 5, 2016-June 10, 2016; Every Tue June 13, 2016 – June 30, 2016, four
City to Hong Kong on May 2, 2016-June 6, 2016; June 10, 2016 – June 30, 2016 every Tue