Inventors and attorneys of record can call Examiners with questions about pending applications. You can call the Examiner at any point in the examination process, and calls do not incur extra USPTO fees. I can personally attest that Examiners make for pleasant conversation, and that there is nothing scary or complicated about Examiner phone calls. However, for maximally efficient examination it’s best to restrict calls to ones that will provide valuable information.
Before a rejection, you could call to gauge your position in the queue. Applications take a long time to process; you might not hear from the USPTO for two years after you submit your application. For a rough estimate, you or your attorney of record can also check Private Pair for the USPTO’s prediction of your first Office Action. You also might want to know your actual position in the queue if someone is infringing on your idea, and you’re wondering whether to file for accelerated examination. In such cases, calling can help you plan or budget.
After a rejection Office Action, you could call to improve your chances of submitting a response that leads to an allowance. If you’re lucky and it’s a clear Office Action with directions on what to fix, you would call to discuss the Office Action and confirm that following those directions will get you an allowance. If it’s a particularly complex Office Action, you would call to set up an Examiner’s Interview to clarify issues brought up in the Office Action, and potentially secure an Examiner’s Amendment.
My clients often ask me to call the Examiner to follow up on pending applications, hoping to get projected dates for USPTO responses. However, Examiners have incredibly crowded dockets and are unable to predict with such accuracy when they will issue your next Office Action. In fact, disturbing the Examiner with multiple follow-up calls may delay examination. Also, if you have filed or plan to file multiple patent applications within the same field, you may well get the same Examiner for multiple applications. Antagonizing the examiner could not possibly smooth your way to allowances.