This function removes select2 JS and CSS of WooCommerce so that theme can use its own.

remove-woocommerce-select2-styles-scripts.php

<?php
if ( ! function_exists( 'remove_select2_wc' ) ) {

	/**
	 * remove_select2_wc.
	 *
	 * This function removes select2 JS and CSS so that 
	 * theme can use its own.
	 */
	function remove_select2_wc() {
		if ( class_exists( 'woocommerce' ) ) {
			wp_dequeue_style( 'select2' );
			wp_deregister_style( 'select2' );

			wp_dequeue_style( 'your-theme-main-css-file' );
			wp_deregister_style( 'your-theme-main-css-file' );

			wp_dequeue_script( 'select2');
			wp_deregister_script('select2');

			wp_dequeue_script( 'your-theme-js-file');
			wp_deregister_script( 'your-theme-js-file' );

			// select2 CSS
            wp_enqueue_style(
                'select2',
                get_template_directory_uri() . 'path-to-select2-css',
                array(),
                '1.0.0'
            );

            // main styles
            wp_enqueue_style(
                'your-theme-main-css-file',
                get_template_directory_uri() . 'path-to-your-theme-main-css-file',
                array( 'select2' ),
                1.0.0
            );

			// select2 JS
            wp_enqueue_script(
                'select2',
                get_template_directory_uri() . 'path-to-select2-js',
                array( 'jquery' ),
                '1.0.0',
                true
            );

            // Main js
            wp_enqueue_script(
                'your-theme-js-file',
                get_template_directory_uri() . 'path-to-your-theme-js-file',
                array( 'jquery', 'select2' ),
                1.0.0,
                true
            );
		} 
	} 

	add_action( 'wp_enqueue_scripts', 'remove_select2_wc', 100 );
}

Looks like there might be some quotes missing on lines 37 and 54.