$mpx=convertto-securestring -string "YOUR_SERVICE_ACCOUNT_PASSWORD" -AsPlainText -force
$mux="SERVICE_ACCOUNT@YOUR_DOMAIN"
$myCreds =  new-object -typename System.Management.Automation.PSCredential -argumentlist $mux,$mpx

#Single Room
suDoubleBookedMeetings -SMTPAddress "YOUR_ROOM@YOUR_DOMAIN" -Credentials $myCreds  `
   -BookingWindow: 14 -EwsUrl "https://YOUR_EXCHANGE_DOMAIN/ews/exchange.asmx" `
   -EWSManagedApiPath "C:\Program Files\Microsoft\Exchange\Web Services\2.2\"  `
   -OutputAsCSV -CsvFile "MY_CSV_OUTPUT.csv"


#Get from Text File
get-content rooms.txt | foreach {suDoubleBookedMeetings   $_ -Credentials $myCreds  `
   -BookingWindow: 14 -EwsUrl "https://YOUR_EXCHANGE_DOMAIN/ews/exchange.asmx" `
   -EWSManagedApiPath "C:\Program Files\Microsoft\Exchange\Web Services\2.2\"  `
   -OutputAsCSV -CsvFile "MY_CSV_OUTPUT.csv"}

#From Get-Mailbox
Get-Mailbox -filter {isResource -eq $true} -resultsize unlimited |Select-Object PrimarySMTPAddress | `
suDoubleBookedMeetings  -Credentials $myCreds  `
   -BookingWindow: 14 -EwsUrl "https://YOUR_EXCHANGE_DOMAIN/ews/exchange.asmx" `
   -EWSManagedApiPath "C:\Program Files\Microsoft\Exchange\Web Services\2.2\"  `
   -OutputAsCSV -CsvFile "MY_CSV_OUTPUT.csv"