This is the 5079th most frequent Polish word.
prezesowi
"Prezesowi" is the dative singular form of "prezes," meaning "to the chairman" or "to the president" in English.
Here, 'prezesowi' is the dative form of 'prezes', indicating the recipient of the action, i.e., the person to whom the documents are handed.
Przekazałem dokumenty prezesowi.
I handed the documents to the president.
In this sentence, 'prezesowi' is again in the dative case, showing the person who is being thanked.
Podziękowałem prezesowi za jego wkład w projekt.
I thanked the president for his contribution to the project.
Here, 'prezesowi' follows the verb 'przysłuchiwać się' (to listen or attend to), which takes the dative case in Polish.