When someone rejects the file, the task is still complete.
You might have noticed that in the animation there is a button for rejecting the file. In this illustration you can see that Brian rejected the file because he thinks slide 2 is incorrect.
One important point to notice is that Brian’s task is still deemed Completed, even though he rejected it.
If someone rejects the file, you’d have to correct the file, and restart the workflow to get approval once more — that is, if you require unanimous approval.