If you are asking about a single-member LLC owned by an S-Corp. pretend the LLC doesn't exist (there isn't any return for a single member LLC unless it elects to be taxed as other than a disregarded entity at least at the federal level) and prepare the S-Corp as if there was no LLC
however, if the LLC has made its own S-corp election complication arise. see this thread
https://ttlc.intuit.com/community/business-taxes/discussion/our-company-is-a-s-corp-we-have-100-inte...
