try this

Hi,

you can change the session value when user change the roles like below one... for this you need to have two sessions,

1. One for old role

2. one for new role

suppose use select the new role from dropdown and click the button, thenin button click event set the below thing...

Session["Old_Role"] = Session["New_Role"].ToString();

Session["New_Role"] = dropdownRole.Text;

while login you can store the default role value in the above two session.