If Vlookup N/A, Input Box to Assign the look up cell to the data table

I export a list of codes that vary daily.
I have a table in my excel document that has most of these codes & each are assigned one out of 4 categories.

I copy and paste my exported codes into a worksheet.
From there I start my macro: it uses vlookup formula to assign each code its category. [this is so I can autofilter later]
However, because codes change/come and go, some codes are not in my table.
When the vlookup comes back #n/a because the code isn't in my table, I want an input box to prompt the user.
The user would then assign the code one of the 4 categories & press OK- this data would be transfered to the table & then allow the vlookup to return the category and continue down the list.


Something like this possible? I know basic coding for vlookups and input boxes, just not sure how to get one on error down a list