A guest is not satisfied with the service of the department you are heading and you come to know about…

The correct choice is: Approach the guest and try to find out the situation and act accordingly.

The most professional response is ‘Approach the guest and try to find out the situation and act accordingly.’.

As head of the department you must own guest complaints: meet the guest, find out what went wrong, and put it right.

Passing it to someone else, doing nothing, or just reporting it to the boss avoids your own responsibility.