Hello Mate...

According to the information available on official website and our careers360 that there is option available for choice filling in second round but not in third round Once candidate is logged in, they will be able to access the list of participating colleges and their corresponding courses. From the given list candidates will have to select colleges and courses in order of their preference. One can fill maximum number of choices. Moreover, candidates will also have the option of filtering their choices through the edit button. Once adding or dropping choices is done, click on ‘Save’ button.

https://engineering.careers360.com/articles/keam-counselling

Hope it helps..