Fade Between to frames?

I just created a rep on GitHub that does exactly what you're asking:

https://github.com/Abrahamh08/Frame-Transitions-AS3

If you are using the time line to place your code,

what you are able to do is create a sprite/movieClip and place it on a new layer above your current layers.  Then give that movieClip a instance name.

Say fade_mc

Then turn that clip .alpha=0

on frame 1 through the code fade_mc.alpha=0

now you said if you click a button it will fade then go to frame two.

so on click of the next button, do not have the frame move from 1 - 2 .. have fade_mc tween from its alpha to a solid state vaie use of theTween class

var myTween:Tween = new Tween(fade_mc, "alpha", Strong.easeOut, 0, 100, 1, true);

next_btn.addEventListener(MouseEvent.CLICK, onClick);
function onClick(e:MouseEvent){
myTween.start();
}

This is the Tween engine of AS3 in the future you may learn of other tweens.  I use GreenSock which is a great tweening engine.

Now this will cause your fade_clip to fade up at 1 second.

now if we listen to the fade complete we can move the time line to frame_2

myTween.addEventListener(TweenEvent.MOTION_FINISH, fadeUpComplete);

function fadeUpComplete(te:TweenEvent):void{

       this.nextFrame()

     fadeDown()

}

function fadeDown(){

var myTween:Tween = new Tween(fade_mc, "alpha", Strong.easeOut, 100, 0, 1, true);

}

Now the last line will fade your clip back to 0 revealing the contents of frame 2.

It takes more than two frames to create a "Fade" effect.

Fade usually means that it will gradually change.  How long you want the Fade effect to last will tell you how many frames you will need. 

For example, by using 24 fps setting, you will need 24 frames for the Fade effect to last 1 second, 48 frames to have it last 2 seconds.