The first reason is that the position held by Cao Hong at that time did not allow him to attack without permission to fight Zhao Yun.

Because when Cao Cao was chasing Liu Bei in Changbanpo, Cao Cao himself was commanding and dispatching the entire army on the top of the mountain. At that time, Cao Hong was standing on the top of the mountain with Cao Cao and did not join like other generals. There was a melee, so it can be seen that Cao Hong's responsibility at that time was to protect Cao Cao's safety, which is what we call a bodyguard.

We all know that the main task of bodyguards is to protect the safety of the target. When the target they protect is not directly threatened or attacked, they generally will not take the initiative to fight with others, because that is very likely to happen. It would put the person he was protecting in a dangerous situation, so Cao Hong only asked Zhao Yun's name instead of fighting Zhao Yun.

The second reason is that I think Cao Hong knew he was no match for Zhao Yun, so he didn’t want to die.

Because both Cao Hong and Cao Cao saw Zhao Yun fighting fiercely on the mountain at that time, Cao Hong, who was also a general, must have thought about whether he could escape in the face of such a chase.

So Cao Hong knew at that time that he was no match for Zhao Yun, so he just rode down the mountain and asked the other person's name. He who knows the current affairs is a hero.