He created a new capital called Akhetaten, or "Horizen of Aten." Today, the site is known as Amarna. He created it as a central focus of his religious beliefs. Things were not going well with him and the priests of the god Amun-Re. The king wanted Aten as the soul god of Egypt. The time finally came when the king disbanded the priests of other sources of worship.
He not only changed his name to what it is now known as, but he created a capital under the same name, showing his immense dedication to his belief. He used that new capital as a central hub for the god's worship. The king was so eager to start religious work in his new capital, that it began there before the city's construction was even complete. He wanted a place absolutely dedicated to the god he served, and the new capital Akhetaten came as a result. I think I fully covered the answer.