what is the {end time} for {Soong Ching-ling} has {position held} as {Vice President of the People's Republic of China} ?
When did Soong Ching-ling step down as the President of the PRC?
SELECT ?value WHERE { wd:Q17132 p:P39 ?s . ?s ps:P39 wd:Q553169 . ?s pq:P582 ?value}
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q17132> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P39> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q553169> .
?statement <http://www.wikidata.org/entity/P582> ?value. 
} 

At what point was Soong Ching-ling no longer PRC President?