Whenever I tried to change the password of FTP, the change did not seem to “take”.

The reason is that the account may be in a cPanel “Demo” mode, in which changing of the password sends success messages, but does not actually change the password.

Solution :

1. Log into WHM as root
2. Go to the “Disable or Enable Demo Mode” under “Account Functions”
3. Choose the account and Press “Modify”
4. Disable Demo mode!