Change_Email_Address.ps1

$UserCredential = Get-Credential

$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $UserCredential -Authentication Basic -AllowRedirection

Import-PSSession $Session

(If Import Session fails run Set-ExecutionPolicy RemoteSigned) and select 'y'

Set-Mailbox -identity current email address -WindowsEmailAddress new email address

Remove-PSSession $Session