Can't you use send_skill_to in that case? You only need an ent_next loop for finding the entity pointer, like this:

Code:
function send_skill_id2(var id, var* skill, var mode)
{
  for (you = ent_next(NULL); you; you = ent_next(you)) {
    if(you.client_id == id) {
      send_skill_to(you,skill,mode);
      break;
    }
  }
}