To change the passwords, you need to access the "Data and management of TA" or the “Trading accounts” section and click on the "blue circle" icon next to the password you want to change. In the popup window, you should enter a new password, confirm it, and then press the "Set" button. The password will be changed instantly.  After changing the password, it is necessary to reconnect to the trading account in MT4 and enter the new password.