Hi, @ononiwujoel. I apologize for the late reply. You don't have to undelegate BP. You just have to enter the amount of BP you want to delegate. For example, let's assume that you have already delegated 3000BP to @upvu. And then you want to delegate 1000BP more. In this case you just have to enter the delegation amount as 4000BP(not 1000BP). Hope this answer was useful. Cheers.