public async Task <ArenaPostResult> Update(int groupId, int personId, GroupMember groupMember) { Action = String.Format("group/{0}/member/{1}/update", groupId, personId); HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, Action); String serializedContent = groupMember.Serialize(); request.Content = new StringContent(serializedContent, Encoding.UTF8, "application/xml"); return(await ExecutePost(request)); }