Sugandha,
There are no activities which will have a long effect on retention. Retention depends on whether the employee feels valued and respected. The same is true for whether they are highly motivated or demotivated, have high morale or are demoralized.
I am willing to serve as the coach of your senior executives in order to create a highly motivated, highly committed, fully engaged workforce of Superstars who love to come to work and will almost never leave your employ. Although there are details of how to do this including exactly why these actions are effective while others are not, the following short video provides the essence of what I advise.
How to Create Engaged Employees (Leadership Skills Training Series)
Best regards, Ben
Author "Leading People to be Highly Motivated and Committed"
Leadership Skills for Managers and Executives.