Yes, it is possible to change your Jagex account username, although certain conditions must be met. Jagex allows players to alter their usernames through the account management interface. However, it is important to note that there may be restrictions on how frequently you can change your username. Typically, players are allowed to change their username once every 28 days.
To initiate a username change, you will need to log into your account on the official Jagex website. Within your account settings, you should find an option related to username changes. Follow the provided instructions, being sure to choose a new name that complies with Jagex's naming policies.
Before proceeding, it can be beneficial to familiarize yourself with the guidelines to avoid any issues. For current and detailed information regarding username changes, including any specific requirements or potential fees, it is advisable to check the relevant sections on the Jagex website.