Given two noun phrases (arguments) and relationship between them, form a sentence that expresses theses arguments with the given relationship.

[Q]: Relationship: 'be head of', Argument/Subject 1: 'president', Argument/Subject 2: 'executive'
[A]: The service has been dubbed Derivatives Collateral Net and automatically aggregates and nets the overall collateral obligations of its participants , explains Art Certosimo , executive vice president and head of Broker-Dealer Services at the bank .

[Q]: Relationship: 'retire from', Argument/Subject 1: 'bill gate', Argument/Subject 2: 'microsoft'
[A]: Bill Gates retired from Microsoft Friday to spend his time in charity work .

[Q]: Relationship: 'conquer most of', Argument/Subject 1: 'mongol', Argument/Subject 2: 'asia'
[A]:
The 40 rays or lines are the 40 tribes of Kyrgyzstan who united to fight Chingiz Khan or Genghis Khan , the Mongol Leader who conquered most of Asia in 1200 .