Hi Nannu,
I believe I know your pain. No matter what you do while trying to access the users application you got redirected to your SSO and therefore lopping you back to the same account (Non admin) so you cannot access, you want to see the old login page, is that right?
If that's the case, try accessing https://<your_server_name>/Users/Login.aspx instead, this will bring you back to the login without redirecting you to the SSO login. This is stated at the end of this documentation. Hopefully it helps and if it does, please mark this as solution!
Cheers,
Hillman