Turn Voice Mail On And Off: Is there a star code?

I know there's *99 to view and set up voicemail, but is there a starcode to have Voicemail switched on or off? Kind of like how there's *66 to switch repeat dialing on, and *86 to switch it off. The reason why I ask this is because I remember when my Comcast service was reset when I got my own modem in February of 2019 to avoid an expensive phone bill with rental fees, the representatives at Xfinity reset everything, and when I next lifted the handset of my phone, voicemail was all of a sudden switched on. The way I knew it was switched on was because I heard the familiar stuttered dial tone. Then I wanted to switch it off, but I wasn't sure if there was a code to do so. So I called Xfinity, and the kind woman I spoke to on the phone helped me to switch it off. Those star codes are very helpful, especially to customers like me who are sight challenged. That would be pretty awesome if there were even voice commands for landlines, where the customer has the ability to activate or deactivate a service or feature by simply speaking into the mouthpiece or the speaker of their phone. Would that be a possibility? Would it cost anything to have this feature added? If so, how much?