I linked my bank and only uploaded transactions from yesterday by mistake, is there a way of changing the dates it reconciles from via linked bank rather than uploading?

Hello there, @Wendypenstraze. I'm here to help you fix the uploaded transactions by mistake in QuickBooks Online (QBO).

We can undo and delete the transactions by batch to remove everything and disconnect the bank account from QBO.
 

1. Click Banking, then go to the Banking tab.
2. Select the bank account.
3. Go to the Reviewed tab.
4. Tap the transactions you want to undo, then click Undo.
    

These transactions will go back to the For Review tab. Just follow the steps on how to exclude and delete them.  

Here's how:
 

1. Go to the Banking page.
2. Under the For Review tab, select all transactions.
3. Click on Batch actions.
4. Select Exclude Selected.
5. Go to the Excluded tab.
6. Select all transactions and click on Batch actions.
7. Tap Delete.

After that, we can already disconnect your bank account:
 

1. In the Banking page, highlight the bank account you want to disconnect.
2. Click the pencil icon and select Edit account info.
3. In the Account window, mark the Disconnect this account on save box.
4. Click Save and Close.

Otherwise, you can create rules to automatically categorize transactions for you. You may want to check out this article to learn more about setting up bank rules: Set up bank rules to categorize online banking transactions in QuickBooks Online.

Once you have completed the sorting process and are ready to reconcile your account, you can use this article: Reconcile an account in QuickBooks Online.

Let me know if you have further questions about managing bank transactions in QBO. I'm always here to help. Have a great rest of the day!