Unity facebook login without login dialog.

Ok i am using latest facebook sdk with unity 5.6.1, "FB.LogInWithReadPermissions" function pops up a login dialog to the user. User has already logged with facebook api on their android device. When user attempts to login, thinks they already logged with facebook on their device and thinks again "why this application wants my email and pass??"

many application dont want email and pass when you press LOGIN WITH FACEBOOK button, because user has already logged facebook on their android device. They prompts to screen for example "continue as clara" or thing like that. i am looking a solution during last four days.

is there any way to do like this?

Thanks. Makinahmet.