Weave altered for loom worker? (7)
I believe the answer is:
treadle
'loom worker?' is the definition.
(pedal operated spinning mechanism)
'weave altered' is the wordplay.
'weave' indicates an anagram.
'altered' is an anagram of 'TREADLE'.
'for' is the link.
(Other definitions for treadle that I've seen before include "Bar" , "Machine foot-lever" , "Pedal operating machine" , "Dear, let a foot lever emerge" , "operate a spinning-wheel" .)