Dear First Name
I would like to inform that I am resigning from my current position of sales manager in your organization. My last day at work will be 15th June.
I am very grateful to you for providing me such great opportunities and supporting me through the last 5 years. ABC has been a great organization to work with and I will always cherish the memories I have of working here.
I assure you of smooth knowledge transfer and transition during my notice period.