A very apt question. What is your answer?
Mine is "Both, at different times." I think we would all agree that, through prayer, God can change our minds. But Scripture clearly and unequivocally tells us that prayer also changes God's mind. No problem with that, right? :-) Or, is He also to be numbered among the immobile "frozen chosen"?
First let me quote from R.A. Torrey because he says so beautifully what I believe: "to pray the prayer of faith we must first of all study our Bibles intensely that we may know the promises of God, what they are, how large they are, how definite they are, and just exactly what is promised. In addition to that we must live so near to God, be so fully surrendered to the will of God, have such a delight in God and so feel our utter dependence upon the Spirit of God, that the Holy Spirit Himself can guide us in our prayers and indicate clearly to us what the will of God is, and make us sure while we pray that we have asked for something that is according to God's will, and thus enable us to pray with the absolute confidence that God has heard our prayer, and that "we have received" the things that we asked of Him."
I think that my will must conform to His, that I must trust in His promises, that I must believe that He is good and means good for me, then my prayers will prepare me for whatever comes my way.
PS, being created in God's image does not make one frozen, but rather passionate 8)