Can Payments Made with Square Test Mode be Converted to Live Payments?

I believe our Square payment form was accidentally left in Sandbox / Test mode while two guests paid for their reservations. A transaction ID was given but the payments are not showing in Square. Is there anyway to process these payments or do the forms need to be completely re-submitted?

The forms need to be completely re-submitted. The payment details cannot be edited from the submission page to charge the user a second time with the same data. This is because the payment details and payment processing is done securely on Square and the details are stored there as well.

Go ahead and inform the users to refill the form and make the payments afresh. A way to assist the user is to provide URL Prepopulation to prefill most of their data into the form and then send them a form link with most of their data filled in.

Refer to this guide: Prepopulating Fields to your Jotform via URL Parameters