... ere a change that is strange (5)
I believe the answer is:
eerie
'strange' is the definition.
(I've seen this before)
'ere a change that is' is the wordplay.
'a change' indicates an anagram.
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'ere' is an anagram of 'eer'.
'eer'+'ie'='EERIE'
(Other definitions for eerie that I've seen before include "Awesome" , "Weird, uncanny" , "Ghostly" , "Spectral" , "Sinister" .)