Surah 2:106 - "Whatever communications We abrogate or cause to be forgotten, We bring one better than it or like it. Do you not know that Allah has power over all things?"
Surah 6:115 - "And the word of your Lord has been accomplished truly and justly; there is none who can change His words, and He is the Hearing, the Knowing."
Surah 10:64 - "They shall have good news in this world's life and in the hereafter; there is no changing the words of Allah; that is the mighty achievement."

The first of the above 3 Surah says the "communication" can be abrogated. The latter 2 Surah say they cannot. Which is/are correct, how/why?