My invoice has some items that lost their links to the initial quotation. how to relink them so remaining amount on the quotation is still correct?

I can help you link your invoice to the initial quotation, @melonrouge.

Base on the scenario that you've shared, the invoice may have been edited. That is why some items lost their links to the initial quotation.

In this case, the best way to relink the invoice to the initial quotation is to delete both transactions. Make sure to take note of the details. Then recreate the quotation and start converting the invoice from there to make sure the link is present.

Here's how to delete the quotation:

1. Go to the Sales menu.
2. Select the All Sales tab.
3. Find the quotation and click it.
4. Select More and then choose Delete.
   
5. Hit Yes to confirm.

After that, you can now create the quotation and then convert it to an invoice.

Doing these steps moving forward will keep the remaining amounts accurate.

To learn more about customising estimates/quotes and other sales forms in QBO, I suggest checking out this article: Customise invoices, estimates, and sales receipts.

Reach out to me in the comment section below if you have any other questions or concerns about keeping track of your sales transactions. I'll be here to help. Have a good one!