c# - What is the correct way to guess either user is registered or admin in window forms? -

i developed windows application want provide security.

my requirement provide few functionalities user , full access admin.

when 1 entered username , password stored role user in database default.

but how give access admin if logged.

i know if provide 1 drop down while adding details sql database. in dropdown give options either user or admin.

i don't want type. have 2 fields username , password , want give option admin if logged.

note: don't want go database , enter admin details there.

is there option while login change option admin?

thanks suggestions.