What will you do as supervisor? 👇
X and Y are PhD students. X graduated, got postdoc/job and leaves the group. Supervisor communicated X's thesis work with help of Y (prepared SI, referencing etc), keeping X as main author and Y as coauthor.
During revision, referees asked to repeat experiments/calculations.
X doesn't contribute at all in revision, not replying the queries. Y does all revisions.
I personally, will switch the authorship as Y first, and then X, marking with equal contributions during revision. What will you do?