string xml = @"<HotelDescriptiveInfoRequest Token='Jan' UserName='username' Password='Password'>
                            <HotelDescriptiveInfos Language='' >
                                    <HotelDescriptiveInfo HotelCode='HY-VISTA'/>
                            </HotelDescriptiveInfos>
                            </HotelDescriptiveInfoRequest>";

            var content = new StringContent(xml, Encoding.UTF8, "text/xml");
            httpClient.DefaultRequestHeaders.Authorization = AuthenticationHeaderValue.Parse("xptohemlmi");

            var response = httpClient.PostAsync(pathApi, content).Result;

            if (response.IsSuccessStatusCode)
            {
                var result = response.Content.ReadAsStringAsync().Result;
            }
        }