Need to set CDR(billsec)=0 when call are not answerd

i have receive all incoming calls into inbound context
then i have used local channel dialing see dialplan mentioed at below .

there are 2 cdr generate 1 for incoming and 2 for outgoing.

what i need when incoming calls are received then i have dialed local channel.
local channel successfullt answerd.
but when sip extension 200 is not pick up the call or call satus="NOANSWER"
i need billsec=0 of both the cdr records.

; here falls all incoming calls
exten => s,1,Answer
exten => s,2,Dial(local/200@internals,30,r)
exten => s,3,Playback(sorrynoanswer)
exten => s,4,Hangup

; here where our phones falls for default
exten => 200,1,Dial(sip/200)

Don’t call Answer (I don’t know why people do this) and don’t call Playback.

Alternatively, don’t call answer, and then call ResetCDR and disable subsequent CDRs before calling Playback. (You may need some silence at the start of the Playback to allow the speech path to establish, or do Answer and Wait after disabling CDRs and before calling Playback.