MAc Layer ACK in Xbee S2

Could anyone advice me as how to activate or get ACK packets on Xbee S2 when the coordinator sends some data to the end node.

In the data sheet it states that and i quote:
“As data is transmitted from one node to its neighbor, an acknowledgment packet (Ack) is transmitted in the opposite direction to indicate that the transmission was successfully received. If the Ack is not received, the transmitting device will retransmit the data, up to 4 times. This Ack is called the Mac layer acknowledgment.”

So how to get this packet or view it on X-CTU terminal when some packets are sent. Which mode to use API or AT.

Responses will be highly appreciated.