https://www.bangkokbank.com/en/Personal/Cards/Be1st-Smart-Card
"If I forgot my PIN, what should I do?
If you forgot your PIN, you cannot reset your PIN by yourself. To continue using your card, you can cancel it and request a card replacement simply by taking your Citizen ID card or passport and passbook to any Bangkok Bank branch in the same province as your home branch and you will be able to replace it with a new Be1st Smart card."
How weird/archaic.
Branch in same province....