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