H1b amendment withdrawal and travel on previous approved petition

Hi… Actually i have a h1b visa stamped till 30 sep 2016. Now my employer had filed an amendment for location change but plan is changed and i have to travel to previous location in approved petition. Can amendment be cancelled and maximum by wen should i be physically in US to apply for an extension. Will amendment cancellation be a problem in future?

They can send a letter to USCIS asking them to cancel the amendment. You can enter US anytime prior to current petition/visa expiration date. As long as extension petition is filed prior to current petition expiration date, you can continue to stay and work in US. To keep aside buffer for LCA, employer-attorney-you back and forth, I would say enter US by Aug 2016.