Email Invoice Which Displays: 'This Transaction is not Editable'

When trying to email an Invoice and receiving a message that states "Transaction is not Editable" is due to the fact that the invoice is in a closed period. In order to email the customer please follow the steps below:

1. Navigate to Transactions > Sales > Create Invoices > List
2. Click on View next to the invoice that you would like to email
3. On the Invoice record please click on the Communications tab and Messages subtab
4. If the email on the To Be E-mailed field is correct, please hover your mouse over the  Actions button located on the top and click on Email