Who to inform after changing phone number

I am planning to change my phone carrier because it is a bit expensive for my current financial situation. I thought I could request MNP from GTN but it turns out they can't so I have to change my number.

I am wondering who to inform after changing phone number (of course besides my personal contacts). Do I have to inform to the city hall for this change like when we change address?

Please share your experience in changing phone numbers. That would be greatly appreciated.

Thank you.

No you don't have to inform city hall, but it would be good to keep your contact information current with places that might need to call you with issues, for example financial institutions or companies like gas or electricity you might need to pay bills for. But if your address isn't changing, then there's no rush for this.