If you made an error on a New CO Code request or CO Code Modification request, you could modify it if NANPA has not started processing the request or issued a Part 3.  You would access the request by using the Modify Pending Thousand-Block request tool in NAS.

[1] For more information, refer to the latest issue of ATIS-0300046, Next Generation Interconnection Interoperability Forum (NGIIF) “Recommended Notification Procedures to Industry for Changes in Access Network Architecture.”
[2] This is required to ensure facilities are available at the homing tandem and that appropriate Service Provider (SP) notification exists; expedited activation intervals or the rescheduling of existing effective dates to less than 45 calendar days have the potential to cause increased blocking and trouble reports for all SPs.