Not usually. When you connect directly to Elektron using the Elektron API, there is only one update rate available. There are various Elektron products that provide different update rates, typically either full market update rates, or trade-safe conflation to 3 quotes per second per item. But that is determined by the product you purchase, and cannot be overridden by the API.
If your application is connecting to Elektron (or any data feed) via a TREP infrastructure operated by your own firm, it is possible for your IT team to configure multiple QoS instances of the same service, and the API supports selecting among them with a QoS parameter. This is rare.