Zip Code Geographies are incorrect

I have a dataset with associated zip codes that I would like to aggregate to the county level. I labeled the zip codes using the "geography" data type, but many of the zip codes are either missing county labels or their location data is simply incorrect. For instance, zip code 10001 (New York, NY) Is listed in Excel as located in Hampden, MA. How can I manually override this or find an updated/corrected zip code listing within excel?