Commenting on the development, IHCL Chairman N Chandrasekaran said Sarna has chosen to resign upon completion of his 3-year tenure as MD and CEO of the company.
"The board respects his decision and has requested him to continue till September 30, which he has kindly agreed to," he added.
Sarna was one of the high-profile recruitments from outside the Tata group made by ousted Tata Sons Chairman Cyrus Mistry. With Mistry's departure from the group, there were speculations that Sarna was also likely to follow suit.
He was considered to be a confidant of Mistry. He had joined IHCL in September 2014 replacing the company's long- serving head Raymond Bickson.
Before he joined IHCL, Sarna was the Group President - Americas of Hyatt Hotels Corporation.