static void MergeDocs(string doc1Path,string doc2Path)
{
	using (var doc2FileStream = File.Open(doc2Path, FileMode.Open))
	{
		using (WordprocessingDocument doc2 = WordprocessingDocument.Open(doc2FileStream, true))
		{
			var doc2Body = (Body)doc2.MainDocumentPart.Document.Body.CloneNode(true);

			using (var doc1FileStream = File.Open(doc1Path, FileMode.Open))
			{
				using (WordprocessingDocument doc1 = WordprocessingDocument.Open(doc1FileStream, true))
				{

					var mainPart = doc1.MainDocumentPart;

					foreach (var elem in doc2Body.ChildElements)
					{
						if (!(elem is SectionProperties))
							mainPart.Document
								.Body
								.InsertAfter(elem.CloneNode(true), mainPart.Document.Body.Elements<paragraph>().Last());
					}
					mainPart.Document.Save();
				}
			}

		}

	}
}