What does the cryptic crossword clue "Range so old, time for a change (9)" mean?

The definition is "Range". The wordplay uses an anagram. anagram of SO + OLD, + TIME = DOLOMITES; definition: "Range" The answer is Dolomites.

Range so old, time for a change (9)

Telegraph Prize Cryptic #3027 | 15 Down | 2019-10-27 flower