Dear [Name]:

I am writing to express my utmost gratitude for the recent promotion I received to [position]. I am truly honored and excited to take on this new role.
I want to thank you for believing in me and giving me the opportunity to prove myself capable of handling more responsibilities. The trust and confidence you have placed in me mean a great deal and I am grateful for your continued support.
I also want to express my appreciation for the guidance and mentorship you have provided me throughout my time in the company. Your leadership has been instrumental in my growth and development and I look forward to continuing to learn from you as I take on this new challenge.
I recognize that this promotion comes with increased expectations and challenges, and I am committed to meeting and surpassing them. I will leverage my skills, knowledge, and experience to contribute to the success of the team and the company as a whole.
In addition, I would like to thank my colleagues and team members for their support and encouragement. I couldn't have achieved this without the collaboration and teamwork of everyone in the department.
Once again, thank you for giving me the opportunity to grow and develop in my career. I am excited about this new chapter and eager to contribute to the success of the company.
Sincerely,
[Your Name]