what is the {end time} for {Deke Slayton} has {position held} as {Chief of the Astronaut Office} ?
Give me the date that Deke Slayton stepped down as Chief of the Astronaut Office.
When did Deke Slayton step down as Chief of the Astronaut Office?
SELECT ?p WHERE { ?g property:position_held resource:Chief_of_the_Astronaut_Office . resource:Deke_Slayton property:position_held ?g . ?g property:end_time ?p }
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?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q3667787> .
?statement <http://www.wikidata.org/entity/P582> ?value. 
} 

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