iisreset command line utility is certainly a very useful tool for stopping a starting IIS.  But if you need to recycle only one application pool either because want to minimally impact other running web applications, or you just want a faster reset time (e.g. running a series of test and want to “reset” the state), then iisapp is for you. Running this script without any arguments (cscript.exe c:\windows\system32\iisapp.vbs or just iisapp.vbs if cscript is your default WSH script host) will display information for all of the currently running web applications, identifying each application pool by its process ID (PID) and application pool ID (AppPoolID).  To recycle only one application pool, use the /p followed by process id or /a followed by the pool name and /r command as follows:

cscript.exe c:\windows\system32\iisapp.vbs /p 2532 /r

or

cscript.exe c:\windows\system32\iisapp.vbs /a YourPoolName /r