Change trains avoiding current model (9)
I believe the answer is:
transpose
'change' is the definition.
(transposing is a kind of changing)
'trains avoiding current model' is the wordplay.
'avoiding' suggests deleting specific letters.
'current' becomes 'i' (symbol for electric current).
'model' becomes 'pose' ('pose' can be a synonym of 'model'**).
'trains' with 'i' taken away is 'trans'.
'trans'+'pose'='TRANSPOSE'
(Other definitions for transpose that I've seen before include "Write (music) into different key" , "show skill at keyboard?" , "Cause to swap places" , "Adjust key" , "Change the order or arrangement of" .)