Passwords can be changed anytime, but is limited to one password change per day. It is not necessary to wait for your password to expire before changing. Also, you will be able to change your password if it has expired.
Your password can be changed in CoreFTP during the login process. To change your password:
If your password has expired you will get an error that says "530 PASS command failed" when logging into CoreFTP. Select the button that has the two blue arrows which is called Site Manager. Then follow steps 2 & 3 from above. Remember after three unsuccessful attempts to login, your ID will be locked and you will need to contact your agency's Top Secret Administrator.