Dragon Bone Change Sprite in Runtime

HI every one,now i have a problem with dragon bone in Cocos 3.x. My dragon bone have a sprite name “a” in the atlas and it’s showed in “loop” animation. I have a sprite name “b” ,“c”,“d” …etc… in assets. And now i want to change the sprite “b” to sprite “a” of dragon bone with code. So can you show me how to do this in cocos.