I would like to correct an incorrectly allocated payment

I can help you change the amount of a received payment, @accounts494.

You can edit the amount of the payment received that you've recorded. Here's how to edit the amount:

1. Go to the Sales menu and proceed to the Customers section.
2. Find the customer whose payment needs to be changed in the list, and click on their name.
3. Click the payment you'll be changing to open it. 
4. On the Receive Payment screen, find the Invoice that was paid with this transaction and change the amount in the Payment field.
5. Click Save and close.

Here's an article that tells you more about receiving and recording payments: Record invoice payments in QuickBooks Online. 

In case you'd like to group multiple payments into one deposit transaction, check the following article for detailed guidance: Deposit payments into the Undeposited Funds account in QuickBooks Online. 

If there’s anything else I can assist you with your invoice, feel free to leave a reply. I’ll be around to answer it for you. Have a great day!