H1 to H4 conversion


My wife entered US on H4 in march,2014 and later got her H1 in 2014 quota.But till now she is unable to find job and now she wants to go back to india due to her health problem.So,Follwoing are the questions that i wanted to ask,

1)if she converts into H4 through my employer, can she travel to india on H4 and return to US on H4 visa without going for visa interview(her H4 stamp valid until Nov,2015)?

  1. how long does it’s going to take to convert from H1 to H4?

3)If she converts into H4,can she able to utilise her H1 after(in case)coming back to US?

Thanks in advance,