How do I drop tune to D? This is making me mad!

[de la mocha]

Why can't these fools just play in standard tuning? So what are my four strings tuned to? I'm only use to EADG! Can some one help me because I need to do it for this song i'm filling in for so I can play it then go home. It's some lady at the studio and her bass player can't make it! Please respond, I have an hour to be there and I don't want to look like the idiot I am by asking at the studio.

[spudmaster34]

i believe you just tune your E string to D

[Wayauste]

Tune your E string down to D...DADG

[de la mocha]

Thanks a million guys. I mean the simple things is what trips me up sometimes!