Changing the nominated occupation and ANZSCO code in an already-approved positive skill assessment by Engineers Australia is a complex endeavor. Your initial skill assessment is closely tied to the specific occupation and ANZSCO code you nominated in your application. To make such changes, you should reach out to Engineers Australia directly to inquire about the feasibility and process of modification. Be prepared to meet the eligibility criteria for the new occupation and ANZSCO code, which may involve a re-assessment of your qualifications and work experience. Additionally, consider consulting a registered migration agent or immigration consultant to navigate the implications of this change on your skill assessment and potential visa application. Changing your nominated occupation and ANZSCO code can have significant consequences, so thorough research and guidance are essential in this process.