This basically makes the endgame playable.
Guide to Save After 6 AM (Glitch)
What to Do
Doing this is really simple.
All you need to do is go back to where you found the robot head in Roxy Raceway and pick it up again.
This will reset the time to 5:15 so you can save while having the second party pass.
The exit’s still work when you go to them while they may be closed still.
This might be patched out later but for now this works.