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I attended an interview on the 16th April 2016. I was informed that I was shortlisted for the second round of interviews. 15 days back I got an email saying that HR has not received any tentative schedule for an arrival from US, who will be taking the 2nd round of interviews and was told they will be updating me soon regarding the schedule and the interviewer details. But it's been 2 weeks; and still I got no schedule for the interview. Please let me know how to follow up and write an effective email to ask for the schedule.