Is there a way to move sales order and invoices from one customer to another without deleting and reentering?

Yes, there is, @814640.
 
You can change the name to transfer the transaction to another customer. Let me guide you through the steps.
 

1. In your QuickBooks company, go to the Customers menu.
2. Select Customer Center, Enter the name of the customer you wish to edit the transaction.
3. In the Transaction section, double click the transaction you wish to change.
4. Enter the name of the customer you wanted to transfer this transaction.
5. Hit Save and Close.
6. Confirm the changes.

 
I added a screenshot for your reference.

For future reference, you can also check out setting up and sending progress invoices in QuickBooks Desktop.
 
Count me in if you need anything else. I'm here to back you up. Have a good one.

@814640 

As additional option, you may utilize the 3rd party migration tool to modify many transactions data in bulk.

https://transactionpro.grsm.io/qbd

https://partners.saasant.com/affiliate/idevaffiliate.php?id=5051_2

Hope it helps.

Hi there, @814640.

Moving forward, you'll want to ensure you select the right customer when creating a sales order to avoid errors and delays.

Also, in case accidentally apply a credit to an invoice, you can refer to this article for the detailed steps on how to remove it: Remove or unapply a credit from an invoice or bill.

Know that you're always welcome to post here anytime you need help. We're always here to have your back. Have a great day and more success in your business!