A landing page with a sign-up form

Hi everyone. Noob question sorry! I've made a landing page with a sign-up form. I gather 3 things, (Email, Name, Order#) with an automation email workflow triggering from that form, it successfully emails people. In this case, it's a courtesy email so that I can follow up and send them a free gift card. But there will be many return customers who need to go through this process again with the same email address. I've found the system doesn't send this email out twice (let's say they return, same name, same email, new order#) Is there an easy fix for this? Thanks in advance!