Updating the additional response verbiage in Exchange conference room mailboxes in bulk

My company recently went through a rebranding and we had to update our company name on the additional response test on some 300+ conference rooms in our Exchange Hybrid environment. As always, PowerShell came to the rescue! In order to do this we took the following high level steps:

• Get all mailboxes of the RecipientTypeDetails type of RoomMailbox
• Get the Calendar Processing properties of each
• For each mailbox with a filled in AdditionalResponse, replace the old text with new text
• If there was a difference between the AdditionalResponse and the new one, then set the mailbox’s AdditionalResponse for the new one, if not then take no action
• Add the results to an array for reporting purposes

Code below (note that this can work for either Exchange On premises or Exchange Online)

$report = [System.Collections.ArrayList]@()

#Exchange On prem
$ConferenceRooms = Get-Mailbox -Filter "RecipientTypeDetails -eq 'RoomMailbox'" -ResultSize Unlimited |
    Get-CalendarProcessing |
    Where-object AdditionalResponse -ne $NULL

#EXchange Online
$ConferenceRooms = Get-ExoMailbox -Filter "RecipientTypeDetails -eq 'RoomMailbox'" -ResultSize Unlimited |
    Get-CalendarProcessing |
    Where-object AdditionalResponse -ne $NULL

$ConferenceRooms |
	Foreach-object {
        $AddtoReport = [PSCustomObject]@{
            Identity = $_.Identity
            PreviousResponse = $_.AdditionalResponse
            NewResponse = ""
            Result = "UNKNOWN"
        }
        $FixedMessage = $_.AdditionalResponse -replace "Contoso\s",'LakeView '
		if ($FixedMessage -ne $_.AdditionalResponse) {
			Try {
                $AddtoReport.NewResponse = $FixedMessage
                Set-CalendarProcessing -Identity $_.Identity -AdditionalResponse $FixedMessage -erroraction top
                $AddtoReport.Result = "FIXED"
            }
            Catch {
                $AddtoReport.Result = "ERROR : $($_)"
            }
		}
        Else {
            $AddtoReport.Result = "NO CHANGE NEEDED"
        }
        $report.add($addtoreport) |
        out-null
        [GC]::Collect()
	}