To get the current Exchange Web Services Internal URL
Get-WebServicesVirtualDirectory -Identity dc-au-ex-02\EWS* | fl InternalURL
To get the current Exchange Web Services External URL
Get-WebServicesVirtualDirectory -Identity dc-au-ex-02\EWS* | fl ExternalURL
To set the Exchange Web Services External URL
Set-WebServicesVirtualDirectory -Identity dc-au-ex-02\EWS* -ExternalUrl https://www.contoso.com/EWS/exchange.asmx
To set the Exchange Web Services Internal URL
Set-WebServicesVirtualDirectory -Identity dc-au-ex-02\EWS* –InternalUrl https://www.contoso.com/EWS/exchange.asmx