If the China Merchants Bank card is reported to be lost in writing, the change of number shall be specified as: 1. International debit cards must change their card numbers in writing. 2. UnionPay card (IC card) reports the loss in writing. The card type remains unchanged, and the card number remains unchanged, otherwise the card number changes. 3. Change the card number when reporting the loss in writing and receiving the card in real time (subject to certain conditions). 4.8-digit old cards, all-in-one cards with BIN numbers of 955550 and 622580, and all-in-one cards with UnionPay card changed for 9 times must change their card numbers.