There are very few options at this moment. Under the existing laws, inventor can file a patent application with identical claims and ask the Patent Office to declare an interference with the patent application of A. The PTO will determine who invented first and award the patent to that party. Under the new law enacted last year, there is a proceeding called Derivation Proceeding which should be initiated by B against A. There may be other options. Please consult an attorney.
The foregoing does not constitute legal advice. No attorney-client relationship exists between me and you. Please consult a qualified attorney before making any significant decision.
As an initial matter, because you're referring to "amendments," sounds like you're referring to a pending patent application, not an (issued) patent.
The claims of the patent application are at the heart of your question.
Your question restated: Can Person B challenge Person A's inventorship of the patent application?
Answer: Yes, if Person B contributed to the claims of the patent application. This could be worked out "behind the scenes" with Person A and if the facts warrant, steps to correct inventorship could be taken with the Patent Office.
Under a typical scenario, an inventor is the owner of the patent application unless the inventor ASSIGNS the application to someone else, including a company (sometimes an employment contract dictates this).
Generally, an inventor is the person who conceived of the ideas expressed in the claims. If multiple people contributed to the claims, they are inventors and must be named; otherwise, the patent (if ultimately issued) could be invalid.
The inventors are named on the Patent. If B invented any aspect of the invention then his name must be included. If B's contribution was making a prototype from the directions of A then he is not likely an inventor. However, inventors have property rights. B should seek analysis from a Patent Attorney.
My comments have been made without discussion. An attorney client relationship has not been established. There may be conflicts which prohibit my providing you with specific legal guidance. Any contact with you beyond these few general words will start with a disclosure of the former employer so that a conflict check can be made. You should discuss with an attorney.
Whether someone is an inventor is determined by the claims of the patent application. If a person conceived the subject matter of one or more claims, then the person is an inventor.
Therefore, whether a person built the first prototype and/or used the teaching skills of another can be helpful to determine whether the person is an inventor, those factors are not determinative.
The answer provided is only for general information purposes and does not constitute legal advice.
Person A invented, Person B reduced the invention to practice, meaning built a prototype. Most likely, unless Person B invented at least one claimable invention, Person A is the only inventor. This happens all the time and it is clear that laboratory technicians try many things under the focus specified by the inventor and they do not get anything because without the inventor there is nothing. Like in every case, the devil is in the details and Person B should sit with a patent Attorney to determine where there is something that belongs to Person B and merits adding as an inventor.
As to challenge, you have nothing yet to challenge, as you only have a patent application that need to be place in form to be allowed.
USPTO Registered Patent Attorney, Master of Intellectual Property law, MBA I am neither your attorney, nor my answers or comments in AVVO.com create an attorney-client relationship with you. You may accept or disregard my free advice in AVVO.com at your own risk. I am a Patent Attorney, admitted to the USPTO and to the Florida Bar.
In addition to the above answers, another option is what is called a "protest" under 37 CFR 1.291. If B believes they are the true inventor, prior to A, of one or more claims submitted by A then this might be viable option. This is assuming A's application is not published or has a notice of allowance mailed and you can actually identify the A's pending application.
B may then submit to the USPTO any information that B deems relevant to the patentability, e.g. derivation. Usually, the trouble with filing a protest under 291 is actually identifying the applicaiton before it is published. There are some practical formalities with submitting such a protest in order for it to be considered by the USPTO, so you might want to consult a patent attorney. You may see this link below for more information. Good Luck!