Point of attack a rower had changed (9)
I believe the answer is:
arrowhead
'point' is the definition.
(arrowhead is a kind of point)
'attack a rower had changed' is the wordplay.
'attack' becomes 'a' (this could be a standard abbreviation I've not previously seen).
'changed' is an anagram indicator.
'rower'+'had'='rowerhad'
'rowerhad' is an anagram of 'rrowhead'.
'a'+'rrowhead'='ARROWHEAD'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for arrowhead that I've seen before include "Water plant" , "A suitable end for weapon" , "Tip of an old projectile" , "Point to a weapon" .)