http://stackoverflow.com/questions/7172725/copy-entity-framework-object

gistfile1.cs

  		// re-link many to many relationship
			var items = new List<ServiceContactInformation>();
			foreach (var serviceContact in original.AssociatedServiceContacts)
			{
				_context.Entry(serviceContact).State = EntityState.Detached;
				var entity = new ServiceContactInformation() {Id = serviceContact.Id};
				items.Add(entity);
				_context.ServiceContactInformations.Attach(entity);
			}
			original.AssociatedServiceContacts = items;
			_context.EnvelopeInformations.Add(original);