**snicker**
Throughout the Bible, God changed mens names (He did not change Paul’s name), in EACH case it was significant as these men became the leader and their role changed (Abraham, Israel and Peter).
Why would the Lord change Simon’s name to “Pebble” or not give him a different role? Then again, how do Protestants know that the first time Christ said Cephas He meant Peter, but the next time He said Cephas he meant himself?