From theme update 3.3 you can replace booking form with owner contact form.
Go to Listing Page Settings -> Show Constact Form instead of booking form? -> YES and Save
The booking form will be replaced by contact form on property / listing page.
If user is logged in, form will look like this
If user is not logged in, the form will have optional 2 new fields for email and name
Emails go directly to property owner email address. If owner is admin, emails go directly to admin email.
Admin can receive duplicate copies for messages by setting his email address here