CA amended returns can be e-filed. Lacerte also seems to support it although I haven't tried. If you prepare an amended CA return with Sch X, Lacerte will produce FTB 8879 for signature with no CD about e-filing not being supported.
ProSeries, on the other hand, does not support CA amended returns as verified by PS users.
---------------------------------------------------------------------------------Still an AllStar
No, the IRS does not currently allow e-filing of Form 1040X. Per theAmended Return FAQs,
At this time, theForm 1040X, Amended U.S. Individual Income Tax Return,is not accepted electronically; only an original tax return may be electronically filed.You must file a paper Form 1040X. If you are due a refund, you will be issued a check and cannot use direct deposit.
I efiled the clients 2018 taxes. They received a 1099R after filing. Amended the 2018 taxes, they will mail in the Federal 1040x, but the California 540x with form X needs to be efiled.