When alone, get changed and stretch out (8)
I believe the answer is:
elongate
'stretch out' is the definition.
(I've seen this before)
'when alone get changed' is the wordplay.
'when' becomes 'e' (I've seen this in other clues).
'alone' becomes 'lone' (synonyms).
'get' is an insertion indicator.
'changed' becomes 'gat' (I can't explain this - if you can you should give a lot more credence to this answer).
'lone' enclosing 'gat' is 'longate'.
'e'+'longate'='ELONGATE'
'and' is the link.
Can you help me to learn more?
(Other definitions for elongate that I've seen before include "Make longer" , "Stretch lengthways" , "grow further" , "stretcher will do!" , "very thin" .)