I would want to know how may leaves are permissible for the company. Second I would want to know the position of this person. ie I wouldnt want to take action on a CEO :-)
The answer would be to ask the employee to get an approval from his superior in written. In all likelihood the superior will not give such an approval. Even if he does one must be "assertive" enough to say NO in case the employee has exceeded the permissible number of leaves that can be taken.
The fact is that there is no right answer. If there was, you would have found it in every book or in every forum, or would be taught in every management classroom. An employee may be a star in the company but you have to remove the diseased chicken from your farm before it infect anyone else, even if it lays the most number of eggs. Your employee needs to be convinced not with your answer but with the fact that you can really do what you claim to do. Phrases like "I think I will..." or "I might do...." or "one option would be..." are not as convincing as "I'll have to take action..." or "I believe that one must follow rules....". Using power words also help in convincing such as "I will assertively tell..." "I will definitely refuse if..."
Avinash Tavares
Trainer & Life Coach
youthempowermentsolutions.org