Resetting voicemail password

During the recent t-mobile data breach (announced 2023-01-19) my wife and I reset the passwords on our phones. After doing that, I was able to use the same password to access my voicemail, but my wife was not. She tried both her old password and new password, without success. 

She knows how to dial #793# in order to force her voicemail password to be the last 4 digits of her phone number; I advised her not to use that bone-headed maneuver. I looked through all the docs on changing account settings, both for the desktop interface and the android interface, but they mentioned only the #793# destroy-my-voicemail-security trick.

Is there a way to use any of the interfaces in order to set a secure voicemail password?