Yes, we have to de-sync the two accounts first, ForestBloom. 

In QuickBooks Online (QBO), if we want to change our old bank account with the new one, we have to disconnect the previous account to make way for the new one. This way, we can have organized data. 

To disconnect your old bank account, we can: 

1. Go to the Bank transactions page. 
2. Choose the tile for the specific bank account. 
3. Hit the Pencil icon and Edit account info. 
4. Select the Disconnect this account on save checkbox. 
5. Click Save and Close. 

Then, we can connect your new bank account. 

I'll add this article about reviewing your downloaded bank and credit card data: Categorize online bank transactions in QuickBooks Online. 

Let me know if you have any follow-up questions about syncing your bank accounts in QBO. Stay safe!