I tried to separate person account by changing record type from person account to business account as advised in this question:
final Account acc = [SELECT Id, recordtypeid FROM Account where id = '001c000000o9d17' LIMIT 1]; acc.recordtypeid = '012D00000006gD2'; update acc;
001c000000o9d17 is a person account, and
012D00000006gD2 is a business account record type. I've got the following error:
first error: INVALID_PERSON_ACCOUNT_OPERATION, person-account cannot be separated.: 
I remember that change of record type worked in previous releases, but it doesn't work in a newly created Sandbox (with Summer 15 release). Googling "person-account cannot be separated" doesn't help a lot (seems like it is either a newly introduced error message, or nobody faced it before).
Is "person-account cannot be separated" error a Summer 15 new feature?