What should an applicant do if their application was abandoned due to no response to an office action?

When an application is abandoned due to the applicant's failure to respond to an office action, the appropriate step is to file a response to the office action. This allows the applicant to address any issues raised by the USPTO, potentially overcoming the obstacles that led to the abandonment.

By filing a response, the applicant can provide the necessary clarification, amend their application, or argue against the reasons for abandonment. This process is crucial because it allows the applicant to rectify the situation without starting over, which would necessitate filing a new application and possibly incurring additional fees and delays.

Other options, such as filing a new application, might not be the most efficient route since it would involve starting the entire application process anew, thereby losing the prior application's priority date. Requesting a waiver does not apply in this context, as there is no mechanism for a waiver in response to an office action. Finally, waiting for re-examination is not a viable option because it does not address the immediate need to respond to the office action that caused the application to be abandoned in the first place.