Creating a new email when offline (mobile device) can only be ended by 'Send' button. The email then is stored in the 'Draft' folder but in 'sending' mode. A user cannot alter or delete this email.

Solution idea:
When offline and creating an email, replace the send-'arrow' by a 3dot-menu with three options:
Safe in Draft
Send when online
Delete

Additional option:
If selected 'Send', still provide the option to stop the send-process or at least make the deletion of such an email possible in the draft folder.