This is a question I answered recently.

Question: Hello, my husband's employer is applying for a J-1 Conrad 30 waiver in early October. I am his dependent. We both would like to travel outside of the US from November to December, and we'll have to get visa stamped from our home country for J-1/J-2. Can we travel while the waiver process is underway? We might be back before the employer applies for change of status to H-1B.

Answer: It depends very much on where your J-1 waiver will be while you are traveling. What I mean is that there are three stages for a Conrad J-1 waiver. It starts with the state program, progresses to the Department of State, and is finalized at USCIS. While your waiver is at the state program you can travel on the J-1. Once your waiver is with the Department of State, I would recommend that if you have to travel, you should return with an H-1B/H-4 once the H-1B petition has been approved. You do not want to risk re-subjecting yourself to the two year home residency requirement.