Banks are closed on Saturdays, Sundays and official holidays . Branches of the banks are within a few meters in the city centers and if one bank does not accept to serve your needs, you can always try the next bank. Look for the sign that says change, exchange, wechsel or kambiyo.
Some banks have lining machines.
You take a ticket by the entrance. A big sign shows the number which is served at that moment. Although the banks use computers, be prepared to wait anywhere from 5 to 30 minutes for a transaction.