One changing locks in church also turned in grave (9)

'one changing locks' is the definition.
(something which changes hair i.e. locks)

'church also turned in grave' is the wordplay.
'church' becomes 'ch' (common abbreviation).
'also' becomes 'too' ('too' can be a synonym of 'also').
'turned' is a reversal indicator.
'in' indicates putting letters inside.
'grave' becomes 'tomb' ('tomb' can be a synonym of 'grave').
'ch'+'too'='chtoo'
'chtoo' back-to-front is 'oothc'.
'oothc' going into 'tomb' is 'TOOTHCOMB'.

'in' acts as a link.