Ambientlight by distance

Is there a way to make the ambientlight change its color from a to b depending on the players distance to an object? I already have the code for detecting the distance but I don't know how to fade the color from one to another.

 var Color1 : Color;
 var Color2 : Color;
 
 function Update(){
     var distancePosition : Vector3;
     distancePosition = transform.position;
     var distance = Vector3.Distance(distancePosition,target.position);
     
     //Code for the change from color1 to color2
 
 }