Log on to your account. Select Account>Account Details>Username>enter new username.
Make sure that the username is:
• 3-15 letters long
• does not contain any special characters or spaces (underscores are okay)
• is not misleading or inappropriate, and
• is not already used on Beem.
Please note that usernames can only be used once and cannot be recycled. Additionally you can only change your username 4 times during the lifecycle of an account.