Component.LoadTexture#frame

Gets or sets the current frame index of the texture being used to render this Game Object.

To change the frame set frame to the index of the new frame in the sprite sheet you wish this Game Object to use,
for example: player.frame = 4.

If the frame index given doesn't exist it will revert to the first frame found in the texture.

If you are using a texture atlas then you should use the frameName property instead.

If you wish to fully replace the texture being used see loadTexture.