I think it means that you DO acknowledge what you are feeling. . .but then you recognize that it is just a feeling and it will pass. So you let yourself experience it, but you try not to hang onto it, but let it flow through you. One visual my t has used with me is to recognize what you are feeling, and then visualize your feeling being a leaf that you place on the water and let it drift downstream. It doesn't mean that you deny the feeling or refuse to acknowledge it. You become aware of it, but try not to get lost in it, or stuck ruminating about it.