Hi there htjagwani@icloud,
Thanks for reaching out about your bank connection. Quickbooks Online is a great tool able to connect to multiple banks' websites in order to import transactions. I can provide some information about updating your bank information.
To reauthenticate your bank, go to the Banking tab in QuickBooks Online, then click on the pencil icon beside the affected to Edit Sign-in info. Enter the bank's connection info again, then Save.
if you have any other questions, feel free to reach out here.