Change parents theme functionality

All I need to change is __( 'Expiry (MM/YY)', 'woocommerce' ) to Expiration Date .
I have tried creating a file just like it to see if it overriders the parents theme /wp-content/themes/customizr-child/woocommerce/includes/abstracts/abstract-wc-payment-gateway.php but that didn't work.

public function credit_card_form( $args = array(), $fields = array() ) {

    wp_enqueue_script( 'wc-credit-card-form' );

        ...

    <label for="' . esc_attr( $this->id ) . '-card-expiry">' . __( 'Expiry (MM/YY)', 'woocommerce' ) . ' <span class="required">*</span></label>

        ...
    );
}

How do I change plugins functionality (just msg) with out hard coding the plugin itself

via Chebli Mohamed