My spouse H4 valid till 2021 and in between h1 got approved and stamped and it is valid only till apr 2020. Poe no issues and currently in Us. Planning to convert to H4 due to job location. Whether previous h4 and EAD still valid or do we need to apply for h1 to h4 and apply for EAD again. During conversion do we need to send payslips.