ESC

Hi, I bought the round trip ticket via US to Hongkong.
My intention is going to take the train from Hong Kong to Shenzhen.
But the problem is that my destination of my ticket  is Hongkong .Will they  not allow me to enter Hongkong to buy a train ticket?
  g. ?; M/ B' f& c! Y' N, W
2 i/ x  X) M0 P+ xIt is urgent! Thank you very much!