change the currency rate for the bank that i had linked?

Hello, @Mary_228. We are glad to see you here in the Community with your first post about changing the currency rate for the bank that is linked to your QuickBooks Online (QBO) account. Let's work together to get your goal to achieve in managing your currency rates.

We understand that dealing with exchange rates and foreign currencies can be complicated. However, doing it in QBO is a breeze. You'll first need to enable the Multicurrency feature to do business in foreign currencies. If you want to use your rate for a foreign currency transaction, you can change the rate when you enter the transaction. I'll show you the steps below:

1. Select + New, then select the transaction you want to enter.
2. From the dropdown arrow, select the Customer or Vendor.
3. In the Rate field, enter the exchange rate.
4. Complete the transaction details
5. Then hit Save and close.

For more insights about multi-currency in QuickBooks Online, please check these articles for reference:

•  Enter and use your exchange rates
• Enter home currency adjustments for your foreign balances

Additionally, if you want to categorize bank transactions and reconcile your bank account so it will match your bank statements in QBO, please refer to the article below for future reference:

• Categorize online bank transactions in QuickBooks Online
•  Reconcile an account in QuickBooks Online
• Learn the reconcile workflow in QuickBooks

If you have clarification about your concern, please don't hesitate to post a reply. We'll be more than happy to assist you and be part of your growing business. Take care of yourself, @Mary_228!