How to modify Login in Azure SQL server

 for example, the login name is 'mysqluserlogin'

1) Enable the disabled login:

ALTER LOGIN mysqluserlogin ENABLE;

2) Change the login password:

ALTER LOGIN mysqluserlogin WITH PASSWORD = 'thisismynewpassword*&£1';

3) Change the login name:

ALTER LOGIN mysqluserlogin WITH NAME = mysqlusernewlogin;