If you are born again, in a sense, you already are transformed/transfigured. However, you still have a fleshly nature.

The walk with Christ is a walk that gradually crucifies the flesh and a walk that results in Christ being gradually formed in you. This change takes place by the power of the Holy Spirit and by your submission to the Holy Spirit. Here is God's simple plan. He leads and you receive His leading. He gives you the faith to believe and the power to obey Him. He actually does His work of love through you by the power of His grace.

Your part is to turn your will toward Him to do His will. When you do that, your flesh dies a little each time and your Spiritual Man, Christ in you, is built up a little each time. As Christ is built up in you, you are set free from the power of Satan by the power of the Holy Spirit.

When you are built up, you are built up as a particular member of Christ the Body.  God speaks to you and faith comes by hearing and hearing by the utterance of God.  When you hear God's voice and don't harden your heart, God shows you His vision of hope.  This is the time when you look into the perfect law of liberty as if looking into a mirror.  You see the Spiritual Man, Christ, in you, and you see Christ the Body, the church, a bit more clearly than you did before.  This revelation will not be without consequence.  You will begin to be the person that God created you to be.  You become more humble, realizing that you have no function outside of the Body of Christ or separated from your brothers and sisters in Christ. (some caveats about hearing God's Voice)

All of this must continue until we all come in the unity of the faith, and of the knowledge of the Son of God, to a perfect man, to the measure of the stature of the fulness of Christ, to one totally complete man, to the measure of the stature of the fullness of Christ.  This is what some people refer to as the rapture, though there is a question whether we will be snatched away to a higher spiritual authority or physically snatched away.  Everyone will not take part in it.  It is for those who have been called, chosen, and found faithful.

For more on this, go here: http://www.seekfind.net/An_Orderly_Way_to_Grow_in_Christ.html