Are you referring to da_admin or just a regular account?
If the later, you can do it through DirectAdmin's user level on the MySQL management page. Click on the database and it will display a lit of users. Then you can Modify the password from that user.
Thanks for replying. I got the issue resolved now. Apparently it wouldn't let me in because of the "too many connections" error. I contacted my hosting company and they solved the problem for me.