Type 1 Update using Import

I am importing service request items from ServiceNow application into QB. I'm using Excel and no API for anything.  

 I am trying to figure out how I could ongoing maintain/update 1 column of the already imported data, leaving all other columns as is.

Example:  after initial import, I want to only update the 'Current Phase' column and not change other columns existing values that were already imported, or manually manipulated through the QB app UI.



Thanks in advance,
William