Keep it short, simple and on point.
It’s been great working with you. I’ve appreciated everything you’ve taught me and I’m extremely grateful for ALL the experience I’ve accumulated in my time working with you and the company.
It’s time for me to move on.
I’ve decided to take my skills and take them to a company where I can leverage what I’ve learned here and continue to grow.
I’m confident in my decision and am excited to start on a new path.
I hope you understand – I’ve spent a lot of time and taken a lot of counsel from close associates.
I’ve made my decision.
I understand this might put you and the team in a bad spot temporarily.
The timing is right for me to move on and take advantage of this opportunity.
That’s it…..short and sweet, simple and to the point.