I found it

exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_PREDICATE_MATCHED_PATH_ATTR, newServiceName);
    exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_PREDICATE_PATH_CONTAINER_ATTR, newServicePath);
    exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR, newUri);