Q: Status immediately changed from With Editor to Required Reviews Completed

Hello! I submitted my manuscript to an Elsevier journal 6 months ago. After the 1st round of review one of the reviewers rejected the manuscript and subsequently the paper was rejected by the editor. After that we sent a rebuttal letter to editor. The editor asked us to resubmit the manuscript. The manuscript had the With Editor status for about 4 months. Two days ago the status date was changed and yesterday the status was changed to under review. Right now the status is Required Reviews Completed. What does this mean? Thank you.