The "resignation" of Turkish Prime Minister Ahmet Davutoğlu marks another step in the continuing concentration of power by President Recep Tayyip Erdoğan. He "resigned" after losing the confidence of the AKP Party's Board, which has increasingly been packed with Erdoğan loyalists. Tensions between the President and Prime Minister have been rising for some time, as described here.
Erdoğan's desire to amend the Constitution to create an executive Presidency is well known, but he lacks a sufficient majority to do so, and a referendum is considered unlikely to carry. When the AKP Board meets this month to choose a successor to Davutoğlu it will presumably choose a more malleable ally of the President.