If you are the creator of a new file, then you should put you name in the Author: line, regardless of how much of the content has been copied from elsewhere in the official parts library or parts still on the Parts Tracker. You don't need to credit the author or authors whose work you have used.
Even with Parts Tracker submission privileges, you will not be able to submit an update an already official part. That needs to be sent to me at parts@ldraw.org and will be "proxy" submitted for you (usually within 24 hours). The !LDRAW_ORG line should show it as unofficial, and you should add a !HISTORY line to describe what you have changed. Changing the orientation of origin is not permissible to ensure backward compatibility. Once your new unofficial version is on the Parts Tracker fuether updates can be made without my intervention.
Even with Parts Tracker submission privileges, you will not be able to submit an update an already official part. That needs to be sent to me at parts@ldraw.org and will be "proxy" submitted for you (usually within 24 hours). The !LDRAW_ORG line should show it as unofficial, and you should add a !HISTORY line to describe what you have changed. Changing the orientation of origin is not permissible to ensure backward compatibility. Once your new unofficial version is on the Parts Tracker fuether updates can be made without my intervention.
Chris (LDraw Parts Library Admin)