Hi there,
Thanks for using Caldera Forms for your restaurant business. At first read, I would think that this is a functionality best to be carried out with a third-party system used to approve and reject reservations, with Caldera Forms simply as the lead collector. At the moment, we do not offer an add-on that would fulfill this need. However, if you wished to create an add-on for this purpose so that all of your information worked seamlessly in one place, we do offer custom plugin development. Read more about that here: https://calderawp.com/custom-plugin-development/. Hope this helps!
Just so you know, we do not generally offer support for Caldera Forms via this board. You might get help from the power users on here, but the channel to get support from us directly is to open a support ticket at https://CalderaWP.com/support. Through that form, someone from our team will follow up about this issue within 1 business day.
Please note that to use our support form, you must have an active license for any Caldera Forms add-on (https://calderawp.com/caldera-forms-add-ons/) or a support license (https://calderawp.com/support/#priority-support).