Question: when did the war department change its name
[{'answer': 'September 18 , 1947', 'provenance': [{'wikipedia_id': '373962', 'title': 'United States Department of War', 'start_paragraph_id': 3, 'start_character': 53, 'end_paragraph_id': 3, 'end_character': 72, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '373962', 'title': 'United States Department of War', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 306, 'bleu_score': 0.96188712955549, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17591430910069019580}, 'section': 'Section::::Abstract.'}]}]