Email and password login, followed by SMS login

Is it possible for a user to login with email and password, then logout, and then login again from the same device using sms authentication? Or will two different accounts be created?
I’m using Android, and what I’m trying to do is to have a way to verify the phone number of a user that has already an account.

When a user logs in with a passwordless connection, a new account is created for them. Your application would need to handle knowing the username/password user, then after SMS login, use Account Linking to link to two accounts. Something along the lines of:

  1. User logs in using username/password (DB connection)
  2. Use passwordless to send sms. Application stores username/password user_id.
  3. Upon successful sms login, application performs account linking of the username/pw + sms user.