To change your mobile number, add a new mobile phone number before deleting the previous mobile number.
Log in to your Yu ID, then on the “Manage mobile phone number” screen, press [Add a mobile phone number] and make additional registration.
(Manage mobile phone number)
After logging in, select Top page > Your profile > “List” of mobile phone numbers
To delete a mobile number, press the “Delete mobile number” button in the field for the mobile number to be deleted.
* If there is only one mobile number registered, complete the registration of the new number first and then delete, as it cannot be deleted earlier than that.
To change your notification destination, note that if your phone number (SMS) is set as the notification destination for two-factor authentication during login, disable two-factor authentication, and then set up a new phone number.
<Related questions>
Q. How do I disable the two-factor authentication setting?
Q. How do I set the two-factor authentication?