Will Turkey agree to buy Patriot system instead of Russian S-400?

There may be a potential deal between U.S. and Turkey over Patriot missile defense system as an alternative to the Russian-made S-400 system Turkey has agreed to purchase.
U.S. Ambassador Kaidanow, the Acting Assistant Secretary of State for Political-Military Affairs said the U.S. State Department was in talks with Turkey and “trying to give the Turks an understanding of what we can do with respect to Patriot.” She did not say if the delegations were meeting at the air show.  
The Source: Reuters