I attempted to migrate my 2821 MGCP gateway to a new PRI from its current T1 CAS and the lines seized.  I was wondering if I followed an improper sequence of actions.  I created a new gateway in Callmanager 4.1.3 for the PRI.  I unregistered the current gateway then registered the new gateway.  I then moved the t1 cable to the new circuit demark.  My next action was to recode the controller t1 on the 2821.  I was able to change the framing and linecode but not the timeslot and service.  When I did a 'sho voice port sum", it still read as e&m with the lines seized.  Rebooting the 2821 did not help.  In order to get back to working order I had to register the origianl gatewayof course but also had to rebuild MGCP.  What steps did I miss or perform out of order?  I need to get this circuit going.  The client is desperate for caller ID.  Any guidance would be appreciated.  Thanks.