48 CFR §52.104

1. (a)The contracting officer must not modify provisions and clauses unless the FAR authorizes their modification. For example—
   1. (1)“The contracting officer may use a period shorter than 60 days (but not less than 30 days) in paragraph (x) of the clause”; or
   2. (2)“The contracting officer may substitute the words ‘task order’ for the word ‘Schedule’ wherever that word appears in the clause.”
2. (b)When modifying provisions or clauses incorporated by reference, insert the changed wording directly below the title of the provision or clause identifying to the lowest level necessary (e.g., paragraph, sentence, word), to clearly indicate what is being modified.
3. (c)When modifying provisions or clauses incorporated in full text, modify the language directly by substituting the changed wording as permitted.
4. (d)When completing blanks in provisions or clauses incorporated by reference, insert the fill-in information directly below the title of the provision or clause identifying to the lowest level necessary to clearly indicate the blanks being filled in.
5. (e)When completing blanks in provisions or clauses incorporated in full text, insert the fill-in information in the blanks of the provision or clause.