Yes, it was in 2004 by this Conference Resolution (note the original resolution was passed in 1984 not 1974):
Quote:
That the 1984 Conference Resolution, ‘This Conference affirms that socialism will entail the immediate abolition and not the gradual decline of the State’, be rescinded and replaced with: ‘That as the State is an expression of and enforcer of class society, the capture of political power by the working class and the subsequent conversion of the means of living into common property will necessarily lead to the abolition of the state, as its function as the custodian of class rule will have ended. Those intrinsically useful functions of the state machine in capitalism will be retained by socialist society but re-organised and democratised to meet the needs of a society based on production for use’