韓　幣　兌　換

恆生同匯豐銀行 唔一定有
(視乎當日有冇人交韓幣 到銀行做兌換)

不過, 機場兌換店一定有.

yes, 恆生同匯豐銀行有得兌換 :)
if you worry that when the time you exchange and they might be out of the currency, then you can ask them to reserve for you, ususally if you reserve at the branches, then that will be ready in the next day; and if you reserve that via phonebanking, then that will take 3 days.