Expos à la mode get potentially to be a role model (3,1,4,7)
I believe the answer is:
set a good example
'be a role model' is the definition.
(I've seen this before)
'expos a la mode get potentially' is the wordplay.
'potentially' indicates an anagram (letters have the potential to spell a new word).
'expos'+'a'+'la'+'mode'+'get'='exposalamodeget'
'exposalamodeget' with letters rearranged gives 'SET A GOOD EXAMPLE'.
'to' acts as a link.
(Other definitions for set a good example that I've seen before include "inspire others?" , "Be a role model" .)