Hi
have the catch wedding pro version and the demo content shows an rsvp at the bottom and is mentioned in your FAQ’s as below
How to add Reservation in theme?
Some of our theme supports reservation. In Premium themes there are 3reservation types to choose from Page, Post and Custom.
How to enable Reservation and choose the type?
Go to “Appearance => Customize => Theme Options => Reservation”
Enable Professional by click option under “Enable On”, entire site, homepage/frontpage, About Page template or Homepage and About Page Template
Then under “Type” choose Post, Page, Category or Custom as per your need
If you choose “Type” as Post, choose post under dropdown of “Post” to display your post as Reservation
If you choose “Type” as Page, choose under dropdown of “Page” to display your post as Reservation
If you choose “Type” as Custom, add custom shortcodes form Cotact form 7 or from Jetpack
Further option to change Title and Description of Reservation
Finally, click on “Save & Publish”
however there is no option for this in the wedding pro theme, can you please explain how you have created the attending RSVP on the demo content please.