Amendments may be made in response to rejections by an examiner.  They may be made to the specification, claims, or drawings.  Amendments may be required to correct inaccuracies between the different sections of the patent application or to allow patentability in light of novelty or obviousness. 

No new matter may be introduced into the disclosure of an application.  Amendments must be signed by a person that has authority to prosecute the application. Any amendments that are sent in without a signature **are not entered into the application.