Worker follows attendant in procession (7)
I believe the answer is:
pageant
'procession' is the definition.
(I've seen this before)
'worker follows attendant' is the wordplay.
'worker' becomes 'ant' (worker is a type of ant).
'follows' says to put letters next to each other.
'attendant' becomes 'page' (page is a kind of attendant).
'ant' put after 'page' is 'PAGEANT'.
'in' acts as a link.
(Other definitions for pageant that I've seen before include "Spectacular display" , "Costumed procession" , "elaborate display" , "Colourful procession" , "Dramatic performance" .)