Changed URL — can't login.

Hi!

It seems one of our admins changed the site URL for our site before doing anything else–now I can’t login at all. If I manually type our site with the wp-login, I get redirected to the new URL, but nothing appears.

I’ve found some fixes, but nothing seems to work or I can’t gain access to the things I need.

Anyone have any ideas? Or a step by step?