an example can be found on AMOSPro_Tutorial:Tutorials/Appear.AMOS
Slowly fades from one screen to another using a range of fancy effects.
Appear source To destination,effect
effect sets the type of fade ranging from 1 to the maximum number of the pixels on your screen.
Appear source To destination,effect,pixels
pixels enters the number of screen points to be affected by the command. It defaults to the entire screen area.