Very few passage American kestrels will bathe in a pan, in my experience-unlike eyases and also passage merlins, which both love a good tub bath.
Nonetheless, passage kestrels will often accept and even seem to enjoy a good misting, and will perform all the typical bathing behaviors you’d expect of one using a pan.
I do this about once every 7-10 days, more often if it’s warm or the bird is particularly crusty from a hunt.