If your son or daughter is working towards their red belt then this can be a big deal for them because it is very difficult to go in the novice belts which are blue and white towards the intermediate belts, which are red, yellow and then green.
They'll need to show that they have an enhanced understanding of this talent and that they have intermediate-level abilities in karate whenever your son or daughter is testing due to their red belt. They'll also have to be very acquainted with fighting. Until they're confident with fighting on average your son or daughter can't progress to any intermediate-level belt.
If your son or daughter is testing because of their red belt; bear in mind that this might take a moment as there are lots of milestones that they'll have to achieve in order to be awarded with the chance to go up belts. You'll need to keep encouraging your son or daughter during this amount of time in case they're met with frustration during their efforts and aren't in a position to progress for their next belt as rapidly as they wish. (you can get some really nice belt displays at http://www.karatebeltholders.com/ check out the different videos they have of them)
Make sure you consult with their teacher about their development and ask what things you can do as a parent to help your son or daughter in their training and make sure that you're clear on what they want to achieve in order to move up to the red belt degree within their training.