How to set (and change) an NTP time source in Windows Server 2008 R2 (SBS 2011 and Vanilla Server). – A Windows System Admin’s Blog

To query the time service:

w32tm /query /status

To change time service:

w32tm /config /manualpeerlist:<IP Address or Host Name>

Tip: After changing service IP/Host, run another w32tm /query /status to confirm the settings show the new time service IP/Host.

Source: How to set (and change) an NTP time source in Windows Server 2008 R2 (SBS 2011 and Vanilla Server). – A Windows System Admin’s Blog