When it comes to fulfilling a request, it can be helpful to express it in a variety of ways. While the phrase "on request" is a commonly used one, there are many synonyms that can convey similar meaning. For example, you could use the phrase "upon ask" or "at demand," which both carry a similar tone of responsiveness. Alternatively, you could use phrases like "as required" or "when needed." Each of these phrases lets the recipient know that they can expect a prompt response to their request. By incorporating these synonyms into your written or spoken language, you can create more varied and engaging communication.