My grandfather used to do this all teh tiem. But it always happeened when he was asleep. Once my grandmother and I were laying in the bed and he was sleep, and he got up and went to use the bathroom. Only thing his body was still in teh bed.

I have heard some allegations though that if you are unexperienced and you attempt it that it's best not to travel far from where your body is, because prolonged separation can make it hard for you to get back. Also if you are delving into the field, you should be ware of those who have more experience, because body abduction of body theft has been known to occur.

One particular procedure that I have tried but did not work for me, and I know has worked for a friend of mine is:

Sitting in a comfortable position back straight, it requires you to be able to put yourself in a relaxing enough trance that you are not falling asleep and at the same time, not conscious, rather in your alpha(it might be beta though) state of consciousness....
things to keep in mind is that you want to feel your body floating up, from you feet to the top of your skull...
your neck should begin to elongate and your head should begin to feel detached from your body, usually your eyes are closed and you begin to see a bright light...I've made it this far
sometimes your teeth begin to tingle, it's more like a sullen vibration in your mouth(like you get cold and your teeth are chattering but softly like)
the passage of exit is usually through the top of your skull when you attempt it in a waking semi consciousness like this...

YOu really want to be able to forget about yourself, forget about what you are trying to do, forget about achieving every step, teh more conscious you are about your surroundings and what you are trying to do the less this will work...

It requires that you lose consciousness but at the same time hold on to asliver, sometimes called the silver chain...

this is why I am never able to achieve this by putting myself in a trance...I usually have to program my self for about a week to achieve it through sleep....

And that works, by me going through the practice everynight for about 5 days, usually on the 6 pr 7th day, I am able to achieve it, but like I said it only happened like 3-4 times for me, this way, what usually occurs is that I get sleep paralysis....