Complex sentence: In October, 2006, Mr. Weinstein petitioned the US Department of State Office of Children's Issues, the designated Central Authority for the Hague Convention, which immediately transmitted the request to the Brazilian central authority, SEDH.
Split into simpler sentences: In October, 2006, Weinstein petitioned the US Department of State Office of Children's Issues under the Hague Convention. They immediately transmitted my request to the Brazilian central authority, SEDH.