ednjcpa,

Yes, Proseries is capable of preparing an amended return for the NYC-204, Unincorporated Business Tax Return.  

Please refer to the New York City government instructions, or contact the taxing authority for detailed information on amending the state return. To indicate an amended return, you may have to check a box on the main form. You may also need to attach a statement of changes made to the return.  Note: The originally filed state/city return is still attached to the original federal return in the original file.

https://proconnect.intuit.com/community/form-1065/help/how-do-i-amend-a-federal-or-state-partnership...

https://proconnect.intuit.com/community/electronic-filing/help/how-do-i-e-file-an-amended-partnershi...

Best,

Mark304