cable modem dbc command

Hi'

I'm trying to move cable modem via the dbc command and it seem to not working

scm d40a.a955.358b wideband channel
MAC Address IP Address I/F MAC DSxUS Primary
State WB
y.y.y.y x.x.x.x C8/1/0/UB w-online 8x4 Wi3/1/0:2

sh cable mac-domain cable 8/1/0 rcc
RCC-ID RCP RCs MD-DS-SG CMs WB/RCC-TMPL
1 00 00 00 00 00 8 0 1 WB (Wi3/1/0:2)
4 00 00 00 00 00 8 0 0 WB (Wi3/1/0:3)
5 00 00 00 00 00 8 0 0 WB (Wi3/1/0:4)

I want to move the cable modem from: Wi3/1/0:2 to : Wi3/1/0:3

test cable dbc y.y.y.y rcc-id 4

and it is not working

do i forget something ?

Thanks