While the revolving door has slowed at Twitter of late, as there aren’t that many people left to go through it, product engineering lead Behnam Rezaei took his turn Tuesday after roughly five-and-a-half years with the company.

Rezaei tweeted about his departure Wednesday, saying in the comments that it was a personal decision, and the company was not undergoing another round of layoffs.

He joined Twitter in August 2017 as senior director of engineering, and he was promoted to product engineering lead in November after Elon Musk took over the company.

Prior to Twitter, Rezaei spent more than 10 years as founder and chief technology officer of technology startup NetSeer, which provided concept-based advertisement targeting solutions for advertisers and publishers and was acquired by Inuvo in February 2017.

Rezaei said in his tweet that he plans to take some time off and go “back to being a full-time papa bear.”

He was also complimentary of Musk, writing in his series of tweets, “It started with managing a recommendation team, then building a data-informed growth org with some of the best people at Twitter, leading to consistent causal audience growth. Then working with machine learning experts across the company to accelerate personalization and artificial intelligence in the core product and, most recently, working with Elon Musk to transform the company toward his vision and texting about product ideas or bugs with him at 3 a.m.”

Rezaei added, “I also learned from up close Elon Musk’s framework to scale the efficiency of a startup to a midsize company to achieve the unachievable. Thank you, Elon.”

He tweeted, “My respect and gratitude to great tweeps and engineers of the past who built Twitter’s core product and infrastructure. This site being here despite all the odds is proof of your excellence. #lovewhereyouworked My kudos to all the amazing people currently at Twitter. Your hard work, brilliance and the heart you bring to work every day to push the mission forward are the most unappreciated stories of the year. Be good, do good work and support each other. I will be rooting for you.”