Thanks for your reply.
I am creating a child theme, and hope to avoid doing edit directly on any of the original files, so the site will be ready for any theme update.
So far I was able to make all the changes I need on the form by creating a contact-page.php file inside my child-theme folder.
But when I made a copy of the original "SketchBoard" folder and put it inside my child-theme folder, the contact page is still pulling sketch-functions.php from the one within "biznez-lite", not the one in my child-theme...
Any suggestion on how to use make changes to the skt_contact_verify() function without having to touch the original sketch-functions.php file?