The same verses that the Pope drives his authority from say that he can so change stuff. Matthew 16:17-19.
17 Jesus replied, “Blessed are you, Simon son of Jonah, for this was not revealed to you by flesh and blood, but by my Father in heaven. 18 And I tell you that you are Peter, b and on this rock I will build my church, and the gates of Hades c will not overcome it. 19 I will give you the keys of the kingdom of heaven; whatever you bind on earth will be d bound in heaven, and whatever you loose on earth will be e loosed in heaven