Downgrade protest by the discontented (6)
I believe the answer is:
demote
'downgrade' is the definition.
(thesaurus)
'protest by the discontented' is the wordplay.
'protest' becomes 'demo' (I've seen this before).
'by' means one lot of letters go next to another.
'discontented' suggests removing the centre.
'the' with its centre removed is 'te'.
'demo'+'te'='DEMOTE'
(Other definitions for demote that I've seen before include "Reduce to lower rank as punishment" , "Move down in rank" , "Reduce in status" , "Put down in rank" , "Downgrade" .)