Once the internship license expires, you would have to submit the finishing documents (i.e. updated transcripts, letter from the university stating they have completed the program and any lacking test scores) an initial application and $125 fee.
NES exams don’t expire. They will stay in an educators file as long as the teacher is currently licensed. If it has been many years of non-activity expired license(s) eventually it will go into another archiving system that we won’t have access to. They would then have to resubmit everything required for license(s) they seek.