I will not take the credit for this But really nice scripts.

Copy this to a text file, save it with a .ps1 extension, and then open it and run it from the Exchange Management Shell ( ./.ps1 )

#ChangeAutodiscoverPath.ps1
#Changing InternalURL Path
$urlpath = Read-Host “Type Internal Client Access FQDN starting with http:// or https://”
Set-AutodiscoverVirtualDirectory -Identity * –internalurl “$urlpath/autodiscover/autodiscover.xml”
Set-ClientAccessServer –Identity * –AutodiscoverServiceInternalUri “$urlpath/autodiscover/autodiscover.xml”
Set-webservicesvirtualdirectory -Identity * –internalurl “$urlpath/ews/exchange.asmx”
Set-oabvirtualdirectory –Identity * –internalurl “$urlpath/oab”
Set-owavirtualdirectory –Identity * –internalurl “$urlpath/owa”
Set-ecpvirtualdirectory –Identity * –internalurl “$urlpath/ecp”
Set-ActiveSyncVirtualDirectory -Identity * -InternalUrl “$urlpath/Microsoft-Server-ActiveSync”
#Changing ExternalURL Path
$urlpath2 = Read-Host “Type External Client Access FQDN starting with http:// or https://”
Set-AutodiscoverVirtualDirectory -Identity * –externalurl “$urlpath2/autodiscover/autodiscover.xml”
Set-ClientAccessServer –Identity * –AutodiscoverServiceInternalUri “$urlpath2/autodiscover/autodiscover.xml”
Set-webservicesvirtualdirectory –Identity * –externalurl “$urlpath2/ews/exchange.asmx”
Set-oabvirtualdirectory –Identity * –externalurl “$urlpath2/oab”
Set-owavirtualdirectory –Identity * –externalurl “$urlpath2/owa”
Set-ecpvirtualdirectory –Identity * –externalurl “$urlpath2/ecp”
Set-ActiveSyncVirtualDirectory -Identity * -ExternalUrl “$urlpath/Microsoft-Server-ActiveSync”
#get commands to doublecheck the config
get-AutodiscoverVirtualDirectory | fl identity,internalurl, externalurl
get-ClientAccessServer | fl identity,AutodiscoverServiceInternalUri
get-webservicesvirtualdirectory | fl identity,internalurl,externalurl
get-oabvirtualdirectory | fl identity,internalurl,externalurl
get-owavirtualdirectory | fl identity,internalurl,externalurl
get-ecpvirtualdirectory | fl identity,internalurl,externalurl
get-ActiveSyncVirtualDirectory | fl identity,internalurl,externalurl

Reference : http://www.seanlabrie.com/2011/script-to-set-internal-and-external-urls-on-all-of-your-exchange-virtual-directories-at-once/