If you want to change the main root FTP Account, then you need to change the password of your cPanel Account. However, if you're going to change the password of a specific FTP Account, you should follow this instruction.
1. Log into your cPanel account.
2. In the
Files section, click on
FTP Accounts Icon.
3. Under the
FTP Accounts list, click on
Change Password or use the
Password Generator.
4. Click on the
Change Password button.
Now you can access your FTP user account with your new password.