Mike has to request lockdown accessory (4)
I believe the answer is:
mask
'lockdown accessory' is the definition.
(face mask)
'mike has to request' is the wordplay.
'mike' becomes 'M' (phonetic alphabet: alpha, bravo, charlie etc.).
'has' means one lot of letters go next to another.
'to request' becomes 'ask' (to ask is to request something).
'm'+'ask'='MASK'
(Other definitions for mask that I've seen before include "Camouflage" , "False face" , "Conceal" , "Face-covering" , "cloak" .)