The most recent version of the Kenku (post 45) has it as an immediate reaction.
Second, I actually thought about that possibility, and was thinking about rewording it to disallow hitting the original attacker, but decided to allow it. For example;
The vagrant sneered at Eerik as he pulled a concealed knife from his boot. "I sure wouldn't wanna speak about the thieves guild like that hereabouts, 'ere I you..."
With flash, the man lunged for him, his dagger's tip speeding towards Eeriks heart. But Eerik only chuckled. Shifting his weight back, the blade barely missed him as Eerik grabbed the handled and deftly twisted it back into the man's chest. The vagrant fell to the ground, gagging on his own blood.
"I'll speak 'bout the guild how I like. Don' know 'bout you, though."
Now, for ranged attacks, it might be harder to describe, but all you need is some narrative creativity.