What can Ken show Sunnyvale's owner in the next ninety days to demonstrate that the resort is making progress?

 

Ken will have to show small changes and the effect that they have had. Obviously, Ken cannot turn the hotel around in 90 days, but by showing the effect of small changes, such as the change in checkout/check-in time, Ken can show that continued progress is happening. 

Step-by-step explanation

To be more convincing, Ken has to enhance revenue because every firm aims to make a profit. Therefore, I believe a satisfying profit and improved job experience wouldn't hurt him. As a good strategy of convincing the owner, the revenue should start increasing at the beginning of the first ninety days, making Sunnyvale's recommend Ken. The resort has been on a decline for years, and if Ken can show improvement, he will get a chance to continue improving.