Multiple Variants...Allow the Customer to Back Out, as needed...

We are a company offering online/remote weddings for customers. We have 4 variants (Keep it Simple, Recite Your Own Vows, Ring Exchange, & Vows and Rings). Sometimes, when our couples are in the middle of the booking process, they change their mind on which variant they want to choose. Unfortunately, when they do, it locks them out of their booking for the 15 minutes. Is there a way to make sure it doesn’t empty out their cart (and lock that time slot for the 15 minutes) when they back out to change a variant? Thank you.