Hi
I am not quite sure what you need help with, you said you have a flow already that you are using Search People?
Flow Trigger Options
1. Manual Flow (because you don't talk about any other way)
or
2/3. When a file is created or Modified in SharePoint or one drive (triggers
or
4. scheduled flow that runs every 1 day or 1 hour or whatever you want
Those are you 4 options for the Flow Trigger
Then these steps after the trigger
1. Use a List Rows in Table (your excel must have an Excel Table around the data)
2. use a condition to verify that the body/value length is greater than 0
3. In the yes side of the Condition
--Add an Apply to each with the input being the body/value output from step 2
--Inside use the Office365Users connector to do a Profile Search using the Name value from the Apply to each loop (current item)
--add an Update a Row in a Table action to update your Excel row.
If, you get an error, because the file is actively locked(because yo are looping through) let me know, we can get around that too.
But this is what I would do.