Open the Euchre.COM app and click on the "Facebook LogIn" button that you will see on the Home screen. This way, you will sign in to the profile created with the Facebook account which you use on your phone.
Please keep in mind that if you do not log in to the same Facebook account that you have used to register in the game, a new account will be created.
Please keep in mind that if you do not log in to the same Facebook account that you have used to register in the game, a new account will be created.