Resolution

You may find corresponding event at Top > Configuration Director > Event Manager > Event Log > use search by order ID or by event type Renewal order has been created and use Repeat Actions button when you found needed renewal order. If action Send notification to customer is assigned to the event then renewal order will be sent to the customer again.

You may also resend any notification which was sent to a customer earlier on emails log page at Top > Configuration Director > Logging and Errors > E-Mails Logs > Outgoing Emails tab > find needed order by its ID and use Resend button in properties of found notification.