change a sprite image in cocos2d iOS

CCTexture2D *firstImage = [[CCTextureCache sharedTextureCache] addImage:@"Image1.png"];

CCTexture2D *secondImage = [[CCTextureCache sharedTextureCache] addImage:@"Image2.png"];

CCSprite *sprite = [CCSprite spriteWithTexture: firstImage];

[self addChild:sprite];

 change the image of the sprite to secondImage:- 

sprite.texture = secondImage;