Office 365 mailbox shows full instead of In-Place archiving

I tried the below commands. All run properly except the last command.

Install-Module MSOnline
$Msolcred = Get-credential
Connect-MsolService -Credential $MsolCred
Start-ManagedFolderAssistant -Identity "Chris"

In the last command, what should I write in place of "Chris"?

PS C:\WINDOWS\system32> Start-ManagedFolderAssistant -Identity "rizwan"
Start-ManagedFolderAssistant : The term 'Start-ManagedFolderAssistant' is not recognized as the name of a cmdlet,
function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the
path is correct and try again.
At line:1 char:1
+ Start-ManagedFolderAssistant -Identity "rizwan"
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : ObjectNotFound: (Start-ManagedFolderAssistant:String) [], CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException