[Solved]Rewrite Caller ID

I have some calls coming from kamailio UACs and forwarded to PSTN through a trunk with Cisco Callmanager and asterisk. My asterisk outbound routes for this trunk are:

[outrt-1] ; to-ccm
include => outrt-1-custom
exten => _931099XXXXX,1,Macro(user-callerid,LIMIT,EXTERNAL,)
exten => _931099XXXXX,n,Set(MOHCLASS=${IF($["${MOHCLASS}"=""]?default:${MOHCLASS})})
exten => _931099XXXXX,n,Set(_NODEST=)
exten => _931099XXXXX,n,Gosub(sub-record-check,s,1(out,${EXTEN},))
exten => _931099XXXXX,n,Macro(dialout-trunk,2,${EXTEN},off)
exten => _931099XXXXX,n,Macro(outisbusy,)

I’ d like for all coming to this trunk (callerid 6xxx) to strip out the first digit (6)

EDIT: Added this rule:
exten => _931099XXXXX,n,Set(CALLERID(num)=${CALLERID(num):1}) and works fine