Updating a form entry creates an additional postmeta entry

When an end user submits a form entry and chooses an item from a checkbox field, a postmeta entry is created with the value they chose. If they then go back and update the form entry and choose an additional value from that same checkbox field, an additional postmeta entry is created, leaving the original as well. I’d like to update that original postmeta entry with all of the checkbox values that are checked. Is this possible?

https://www.ads-software.com/plugins/gravity-forms-custom-post-types/