How can I have specific <select> tags opt-out from Select2?

Hello. I have inherited a Wordpress site and theme from another company, and I need to make changes to the original design.

The theme comes with Select2 pre-installed, but the customer has a specific look and feel in mind, and would like custom styled select list in place on the front screen. These styles do not get applied with select2 installed.

How can I opt-out specific groups from the select2 changes?