Yeah, I like Larry's option 1 better too :)
This code could be added wherever in your current process you are putting the data from the file into the table.
How you do this depends on how you are importing the data.
If you are pulling the data directly into the table, you should just fire the REPLACE as Larry has it.
If you are going line by line and INSERTing or GATHERing, you could change the memvar at that point.
m.phone_num = transform(m.phone_num,"@R 999-999-9999")
m.call_min = m.call_min *.1
INSERT INTO mytable FROM MEMVAR
Insanity: Doing the same thing over and over and expecting different results.