Change trains, missing one and not getting to express? (9)
I believe the answer is:
transmute
'change' is the definition.
(I know that transmute has the is a more specific form of the action change)
'trains missing one and not getting to express?' is the wordplay.
'missing' indicates named letters should be taken away.
'one' becomes 'i' (Roman numeral).
'and' means one lot of letters go next to another.
'not getting to express?' becomes 'mute' (unable to express things in speech).
'trains' with 'i' taken out is 'trans'.
'trans'+'mute'='TRANSMUTE'
(Other definitions for transmute that I've seen before include "Alter" , "Change the nature of (something)" , "published obscenity in unfinished number" , "Change eg into gold" .)