Hello,
If you just want to make a new link on each listing, you could hide ‘send enquiry’ with CSS and either:
1) Add a widget that only shows on Detail pages that has a link to a different form
2) Add a custom field (URL) that is an Admin only field with the link you want, then style that as you like
If that isn’t what you are looking for, maybe you want to customize?
For V1, we have an example of how a 3rd party plugin can be used instead of or in addition to the send enquiry feature:
Dynamic shortcode: https://wpgeodirectory.com/formidable-forms-in-geodirectory-tabs/
However, if you are leaning towards this type of integration, we would recommend at least trying it out with V2 first to see how much easier it is with Ninja Forms as an example:
https://wpgeodirectory.com/geodirectory-v2-ninja-forms/
For more about V2 see:
https://wpgeodirectory.com/docs-v2/geodirectory/overview/
Let us know if those aren’t what you are looking for.