What does the cryptic crossword clue "Seat is moved for daytime rest (6)" mean?

The definition is "rest". The wordplay uses an anagram. anagram of SEAT + IS = SIESTA; definition: "rest" The answer is SIESTA.

Seat is moved for daytime rest (6)

Daily Mail Cryptic #16993 | 9 Across | 2022-12-20 flower