hard to soft viterbi decoder

Hi, In viterbi decoding for puntured convolutional code how I can change the mode of decision following this code : if code_rate==1/2 decoded = vitdec(R_demod,t,tb,'trunc','hard'); elseif code_rate==2/3 coded = -2*R_demod+1; nicode = zeros(1,2*length(coded)*code_rate); nicode(1:4:end) = coded(1:3:end); nicode(2:4:end) = coded(2:3:end); nicode(3:4:end) = coded(3:3:end); decoded = vitdec(nicode,t,tb,'trunc','unquant');