public static async Task <User> removeProxyId(string externalId, string proxyIdToUnregister)
{
User user = new User();
user.external_id = externalId;
ProxyId proxyId = new ProxyId();
proxyId.unregister = proxyIdToUnregister;
user.proxyId = proxyId;
string route = APIRoutes.addRemoveProxyIdWithExternalIdRoute(externalId);
SMResponse m = await AsyncClient.put(route, ConstructSMRequest(user));
return(m == null ? null : m.user);
}