Lookup Value And Copy Next Column Value To Another Cell

I'm having a hard time understanding the Find function and getting the syntax correct. For the example below I need an entire function that will look up the most previous value of 'Incident_Number, and copy the corresponding 'Description' into the last record.

My spreadsheet has an Excel Table with column A titled 'Incident_Number' (a Number) and column B is 'Description' (a String). Incident_Number may contain cells with duplicate entries, but in each case, there will be a corresponding 'Description'. I already have a macro that creates a new record for either 1) a New Incident, or 2) an existing Incident. If I'm creating a new record for an existing Incident, what I need to be able to do is auto populate 'Description' with the value in the previous record that has the same Incident_Number.

In the example, the macro should copy "The battery was replaced" from the most previous record whose incident number is 1001 into the new record.

Incident_Number Description
1001 The battery is dead
1002 No power at the console
1003 System crashed
1001 The battery was replaced
1004 something else
1001 ?? (should read, "The Battery was replaced"