title: Phaser update sprite texture
body: <p>I have a problem updating a sprite.</p>
  
  <p>I created a function to change clothes. This should work like:</p>
  
  <pre><code>// Something like this.
  pet = pet_with_hat
  </code></pre>
  
  <p>There is code at <a href="https://github.com/futer/pandachii" rel="nofollow">https://github.com/futer/pandachii</a> in in js/main.js, line 387.</p>
  
  <p>When I write this:</p>
  
  <pre><code>this.pet = this.game.add.sprite(90,90, 'pet_black_hat')
  </code></pre>
  
  <p>There is an error:</p>
  
  <pre>
   Uncaught TypeError: Cannot read property 'health' of undefined
   GameState.update @ main.js:194
   Phaser.StateManager.update @ phaser.js:16628
   Phaser.Game.update @ phaser.js:23092
   Phaser.RequestAnimationFrame.updateRAF @ phaser.js:41421
   _onLoop @ phaser.js:41407
  </pre>
  
  <p>How do I change the sprite image for this pet to another?</p>
  
  <p>I will be grateful.</p>