My name was missed in several patents issued by a Company with whom I was in the past. I contacted a very experienced Attorney in Employer-Employee Relations for an advice. His belief was that I cannot do anything if the Company does not want to add my name as an Author of a patent owned by The Company. However, this is a matter of Authorship but not a matter of Ownership. In Authorship it is only the Person (the Author) who matter. A Company may own the Patent but they do not own the persons names.
I gave the Attorney the following example: I own a Mercedes car and in my garage I replaced all the car signs of Mercedes with those of GM. I can do that because I own the car, but I cannot drive such a car on the street - It is illegal to change the Authorship (in that case Mercedes). He said "Very interesting example - I have not thought about such situation" but he remained firm on the belief that I cannot do anything to protect my name as an Author if the patent is owned by a Company, and the Company does not want to include my name regardless that the key idea of the patent is mine.
In other words, I think it is illegal to ignore an Author of a patent, and it is a personal care of the missing Author in the list this to be corrected. It is not a Company care. I believe that a Person do not need an agreement by the Company to file a claim for Patent Authorship and support his claim with enough evidences.