Is it possible to change a username for an existing account?

Good Afternoon,

I need to see if it is at all possible to have the username of an account changed? The employee that set up the account is no longer employed with us and the company would like to have the account set up with a more company friendly user name rather than that of an ex-employee.

The username on the account in question is carigrafton

Thank you for your assistance in this matter.

Margaret Hayes