A family of Microsoft word processing software products for creating web, email, and print documents.
You will need bookmark the word in B2 and then use the following formula in B5 (assumes that your table is 2 rows by 5 columns as in Word the columns are A, B, C, etc
{ IF { REF B2 } = "Refund" { = B3 - B4 } }
The above assumes that the bookmark name used is B2.
You must use Ctrl+F9 to insert each pair of field delimiters { } and you use Alt+F9 to toggle off their display.
You would need to be very careful that if the word in B2 is changed that the bookmark is not destroyed when it is changed