What does the cryptic crossword clue "Agreeing to re-write hymn on air (2,7)" mean?

The definition is "Agreeing". The wordplay uses an anagram. anagram of HYMN + ON + AIR = INHARMONY; definition: "Agreeing" The answer is INHARMONY.

Agreeing to re-write hymn on air (2,7)

Guardian Cryptic #29277 | 30 Across | 2024-01-12 flower