i mistakenly filed an 1120 tax return for a client before i received his notice of acceptance for the same year as an scorp.  how can i amend the return from 1120 into 1120s, i read online that i need to file an amended 1120x as zero then file a new form 1120s, but i am concerned that client will be hit with penalties for late filing 1120s which can be hefty.  please advise on the best approach.

thank you,

Alex