In order to create a remote powershell session to 365, open Windows Powershell and run below commands:
$UserCredential = Get-Credential
and enter your 365 credentials when prompted.
Then type:
$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $UserCredential -Authentication Basic -AllowRedirection
Import-PSSession $Session -DisableNameChecking
To add required smtp address:
Set-UnifiedGroup -Identity "Group Name" -EmailAddresses: @{Add ="[email protected]"}
To promote as a primary smtp address:
Set-UnifiedGroup -Identity "Group Name" -PrimarySmtpAddress "[email protected]"
To remove the old address from the group:
Set-UnifiedGroup -Identity "Group Name" -EmailAddresses: @{Remove="[email protected]"
To end your Exchange Online Powershell session:
Remove-PSSession $Session