Have a new client that had an LLC in 2016 and prior with another LLC member that split up on 01.01.17 and filed 1065's through 2016. Beginning 01.02.17, client will file (he is late filing his 2017 personal returns but I think on extension for 2018) a schedule C for the entire 2017 activity since the LLC became a disregarded entity at the beginning of 2017. Then, for 2018, we plan on making a late election filing of entity change from disregarded entity to corporation together with a concurrent S corp election via form 2553. My question is with these two changes on the same legal entity of the LLC, do I need to apply for a new federal ID# when changing from partnership filer to schedule C individual filer and then again from individual filer to corporation?
Followup question: During the partnership, accrual basis was used. When switching to a schedule C, can taxpayer choose cash basis without filing a form 3115 because the LLC, though the same legal entity, becomes a new tax type in 2017? Even if the FID# is not changed?