・To Remove
If your account is linked with other social media accounts, go to Profile > Settings > Account and under Phone Number select Unlink Phone Number.
If your account is not linked to other social media accounts
1. Link your account with a social media account (Twitter, Google, Facebook, LINE, Apple ID).
2. Go to Profile > Settings > Account and under Phone Number select Unlink Phone Number.
・To Change
Go to Profile > Settings > Account and under Phone Number select Update Phone Number.