Recently, I submitted a paper to a journal. The paper was reviewed and the reviewers asked for some changes. I revised the paper and sent it again. The paper was reviewed again and after a few months the status was shown as "reviews completed". But the status was again changed to "editor assigned". Could you please explain to me what does this imply?
Each journal has its specific take, but the most likely explanation is that the peer review process took longer than usual and the same editor had expired and had to be reassigned, or that he was no longer interested in handling your manuscript and it was thus assigned to another editor.
In most busy journals several associate editors cooperate with the editor-in-chief, and it is likely that your manuscript was switched from one associate editor to another one.