I was able to successfully do this by editing /wp-content/plugins/business-directory/function.php
In line blocks 14 - 32, you'll have the construction of the form itself. Locate the asterisks for the fields and delete them. This will remove the asterisks from the front-end and the user getting misinformed that a field is required when it indeed will not be.
Line 777 - 810 will contain the actual validation check statements. Simply comment out the lines that you do not want the script to validate for. Here is an example, where I commented out the "Description" field requirement on Line: 794 - 798:
$errors = empty($post["description"])?
"Please enter a brief description for the organization.<br/>":
"Invalid character(s) in $adjective description.<br/>"