Zelenski replaces the current Minister of Defense, he wants to appoint the previous first intelligence officer to this position

Ukrainian Defense Minister Oleksiy Reznikov may leave his post, and Kyrylo Budanov, former head of the Ukrainian military intelligence service GUR, may be appointed in his place, writes Ukrainian Justice.

This media refers to its unnamed interlocutors and sources from the Ministry of Defense and the Office of the President of Ukraine.
Allegedly, they are currently considering which position Reznikov should be relegated to, since no one doubts that he should remain in Zelensky's team. One of the options is the appointment of Reznikov as the new minister of justice, and the current minister Denis Maljushkin to be sent as an ambassador to one of the European countries.
The reasons are currently unknown, but the Ukrainian president recently announced major changes in the Ukrainian military and state leadership.
One of the reasons is probably the heavy losses that the Ukrainian army has in the battles around Donbass