How to change the dimensions of the Sprite object?

Hi all,
I am new to Flash and ActionScript 3.0 environment. I have only basical knowledge regarding this platform.

My issue/problem starts here:

  I have a Sprite object on the stage. 

What I should do in order to change the dimensions (viz.,size,colour, or both ,etc) of this Sprite object, when it gets clicked?

My sample code looks like this:

var circle:Sprite = new Sprite();

function onStage(e:MouseEvent):void
    trace("in stage's event listener");  

function onCircle(evnt:MouseEvent):void
   trace("Inside circle's event listener.");
**   // required code should be added here.....**

I think, you have got my point.
Please, anyone help me regarding the issue by providing a simple solution.

I will be waiting or your repliesā€¦
Thanks in advanceā€¦