The CurrPorts tool from Nirsoft can easily close a TCP/UDP connection without kill the Process via Windows command line
cports.exe /close <Local Address> <Local Port> <Remote Address> <Remote Port>
Example:
cports.exe /close 172.24.3.102 51512 172.25.1.206 8007
Download: CurrPorts
Refer: https://superuser.com/questions/384758/how-to-kill-a-particular-tcp-connection-in-windows/384761#384761