You can, with caution.
I was told by someone that I trust that if the sand is less than a year old, no problems.
Any more than that, the organic matter that has collected/built up in the sand can be released and cause your parameters to spike/drop to dangerous levels.
Keep in mind, I've yet to have a tank for even a year now so...
Wash it well in a bucket with tap water. Then drain as much water out as you can. It won't be live anymore but that is fine. Your live rock should do fine. In time it will be live again.
