This should be done before updating the Application Pool password in case the host rejects any planned password due to complexity or other rules.
In the MMC Console, Select View on the one session you left open in Step 2--right click and select View for a new terminal emulator pop-up.
You should see a screen something like this--Press F3
Next will be this screen--Press ENTER
Now there is the Signon Screen -- the Production system looks different than this one, but sign-in with the FLYNETSVC userid and active Password.
Here is an example of the initiation of a password change on an IBM i (AS400) -- press F9 to display the password change where you will be asked to (typically) enter the old password and the new password twice to confirm.