You can request a reschedule with the details. It is up to USCIS to schedule the interview. The processing times, both those posted on the USCIS website and those listed on receipts are just rough estimates.
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Yes, you can request to have the interview rescheduled. Please provide them with the specific dates when you are back in the country and available for the interview. They typically have no issues with rescheduling. The only risk is that there might be a delay in scheduling another interview by USCIS, but that's rare. Good luck!
You can request the rescheduling but I'd jump at the chance to finish and travel as a citizen. If you are concerned there is something incorrect with your application, then retain counsel to attend the interview with you.