Yes, emotional transmutation is possible, and far easier than it seems. Every human being has felt negative and positive emotions at least once in their lives. All it takes to transmute one into the other is access to the memory.
i disagree with the advice about detachment. While I do agree that it is a powerful and useful state, I don’t think it is what you need. You need transmutation NOT neutralization.
This is what I do and you might find it useful as well (it has some very powerful magical applications too):
Immerse yourself in your negative state, sink into the negativity, and then, once you are there, accept it. Understand that these feelings are okay. They are useful, and they serve a purpose, but also know that they are under your control, not the other way around. The easiest way I have found to do this is to simply talk to myself in my mind, while experiencing the negative state. Simply tell yourself that you accept these emotions as part of yourself, because that is indeed what they are, but they do not rule you. Sit with them for a bit, and realize they have something to teach you. They are not “bad,” they just are. Do not try to escape from them, like most people do because they are afraid to face them, because if you do, they will just follow you. Sit and allow the experience.
Once you have brought yourself to this acceptance and understanding of the negativity (even if it is just a shallow level of acceptance) use your Will to access your memory for a time when you experienced a positive state. It doesn’t have to be something big, like falling in love, but instead go for something simple, like the enjoyment of a good movie, or the taste of a good meal. We all have such experiences in our memory, regardless of what has happened in our lives. We all have moments where we forget what is happening around us and lose ourselves to an experience. I vividly remember sitting on a bench in a park, overlooking the ocean, and just enjoying the breeze, even though at that time I was homeless and living in a shelter, and under a lot of stress. I got out of myself for just a moment and saw the beauty around me.
Focus your memory on the experience, and let it play out in your head for a moment or two. As you do, begin to place your focus on the feeling rather than the scenario that gave you that feeling. Eventually, if you do this process often enough, you will be able to divorce the emotion from the experience completely, and call it up at will simply by focusing on it. Once your focus in on the feeling, sit with it, in the same manner that you did with the negative state. You will find that your physical body will follow your focus, and will begin to relax. Accept this positive state as well. Know that it is not better than the negative one, but it simply is what it is. Begin to talk to yourself again, and remind yourself that you rule your emotions, they do not rule you. Both those states you consider to be negative, and those you consider to be positive have their place in your physical experience, and each has knowledge to impart to you. Stay in the emotion as long as you like. You could even anchor it to a gesture, so that you can access the emotional state whenever you wish, rather than relying on your memory.
This becomes very useful in magick, because it enables you to transmute the desperation you feel for the outcome that brought you into ritual in the first place, into the feeling of success at the conclusion of your ritual, thus neutralizing the “lust for result,” and getting out of your own way.