China Merchants Bank Credit Card can only be exchanged for China Southern Airlines mileage with a credit card jointly signed with China Southern Airlines, and these points will not be accumulated into China Merchants Bank Credit Card points. China Southern Co-branded credit cards spend 1 mileage per card 18 yuan/USD 2. The mileage of supplementary cards is accumulated to the membership number of the main cardholder, but the supplementary cards are not accumulated separately.