Canvas to Canvas In one Scene

Ill input it in button. But my statement is wrong

 using UnityEngine;
 using UnityEngine.UI;
using System.Collections;

   public class Director : MonoBehaviour {
      private GameObject mainMenu, options;

  void Awake (){
	mainMenu = GameObject.Find ("MainMenuCanvas");
	options = GameObject.Find ("OptionCanvas");
	}
void Start () {
	mainMenu.SetActive (true);
	options.SetActive (false);
}
void Update () {
	if (mainMenu.SetActive = true) //what statement should i replace here?
	{
		mainMenu.SetActive (false);
		options.SetActive (true);
	}
	else if (options.SetActive = true) 
	{
		mainMenu.SetActive (true);
		options.SetActive (false);
	}
  }
 }

Do you bleed? You will!
Do you read the API? You should!