// Expose a reference to a flare in the inspector
var newFlare : Flare;

// Assign the flare
light.flare = newFlare;

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    public Flare newFlare;
    void Example() {
        light.flare = newFlare;
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    public newFlare as Flare

    def Example():
        light.flare = newFlare