Let me begin describing what intending is by contrasting it to intentionality and representation. Representing is best described as a relation between a system and objects in the world. Because the representational relation involves both the system and the object, properly speaking it is part of neither, but rather a description of them both. Is intentionality representation? It certainly seems like a good fit, since we expect intentionality to be the connection between a mental act and its contents in the world, and representation can certainly fill that role.  The connection between the mind and the external world cannot be captured completely by representation, however. Certainly we experience our mental events are about objects, and not just about objects in general, but specific objects. To describe this feature of the mind I use the word intending. Perhaps this is not the best term, since it could be easily confused with intentionality, but since they are so similar I thought it best to give them similar names.
If intending is part of the mind clearly it can’t be a relation between the mind and the external world.  One way of describing intending is as a horizon of experiences that define our conception of any object, an idea developed by Husserl.  [3b] By horizon of experiences we mean that the idea, or act of an intending an object, is defined by a number of perceptions that we expect we could have about such an object. This is not to say that we could have all the perceptions in the horizon of an object at once, in almost all cases it would be impossible as the horizon includes perceptions of both the front and the back. The idea that a horizon of experiences defines our conception of an object might seem acceptable for unique objects, such as people, but how can we handle concepts such as dog, where there is not one way of looking like a dog? What we have to abandon is the naïve assumption that the horizon is defined by a number of perceptions all from different “points of view”, so to speak. There are a large number of possible visual perceptions even from the same “point of view” that are part of the horizon, for example in the case of the concept “dog” the horizon is made up of all possible perceptions of all possible things that could be a dog.  Even though a given horizon is composed of an infinite number of perceptions, each one picks out an object or set of objects from the vast number of all possibly experienced objects on the basis of those perceptions. Thus they make a good candidate for what we mean by intending; defining what intending a specific object is by appealing to a distinct horizon makes no reference to how things really are. By making use of horizons there is no need to posit a necessary connection between the act of intending and the objects in the external world, but at the same time we have a distinct notion of how one object can be intended by a thought act while another is not.
One objection that might be raised against the existence of such a horizon or its ability to be what is behind intending is that our physical minds don’t have the capacity to hold horizons as described here, since they are infinite in size. What this objection doesn’t take into account is that the description of horizons given above is not meant to describe how they are physically realized but how they are experienced and pin down an object or objects as being intended. As to how they might be realized physically consider the equation x > 2, In this equation we have defined x as an infinite number of possible values using only three symbols. Similarly the horizon for an object is likely defined by a small number of mental “rules”. We could have defined intending in terms of those rules instead of the horizon, since they are equivalent. I didn’t, however, because the exact form and nature of such mental rules is the subject of much debate, but the fact that they give rise to a horizon is not.
The last piece of the puzzle is how intending relates to representing. In many, if not most, situations intending and representing seem to overlap, where when one is intending something one is also representing it, and vice versa. There are, however, cases in which the two come apart. It is possible to represent objects that we aren’t or can’t be intending, for example when a patient with blind sight successfully reaches for objects they can’t see. They must be representing the object in order to direct their actions, but since they aren’t conscious of the objects it is equally apparent they don’t intend them. Intending also has the possibility to be directed at objects that don’t exist (for example thinking about unicorns), and to be mistaken (intending one object when the actual presented object is something else), while representation can be neither. The best way to describe intending then is as part of the conscious mind that is responsible for the ability to represent things  but that may be carried out even when representation is absent.
1. More on representation / intentionality here
2. To say that it was would simply collapse it into representation, as well as to run up against the many problems facing externalism (see here).
3. Of course Husserl is somewhat obscure in places, so there are probably other readings of his ideas concerning the horizon, don’t cite me as an authority on Husserl, I’ll leave that job for David W Smith.
3b. And it turns out that while the ideas about intending presented here are certainly something Husserl might have agreed with it is definitely not what he meant by horizon. I told you not to cite me.
4. I should note that the horizon, which determines what we are intending, is not the all there is to thinking about some object. We often associate non-perceptual ideas with an object, for example, ownership, and the horizon does not capture these aspects of thought. However, the horizon does capture what matters for intending an object “in the world” which is what matters here.
5. Remember that representation is a correlation between property of the system and a feature in the world, and that the property of the system is responsible for activity as if that feature of the world is as it actually is. The horizon of an object is a conscious property that is correlated with the actual object (via perception), and that horizon informs our behavior and is responsible for it being properly directed at the world. Thus without intending consciousness wouldn’t be able said to represent anything, even though intending is not the same thing as representing and representing can be carried on without consciousness.