If you want to change your partitions on KDE neon, or in fact on a range of other drive formats as well, there is a very good partition manager called KDE Partition Manager. With it you can create, destroy, resize, move, and backup partitions in formats such as ext2, ext3, ext4, fat16, fat32 and ntfs. There are also many other formats where not all the options are available.
To install KDE Partition Manager in KDE neon, open Konsole and type,
sudo apt install partitionmanager
Then press enter, authenticate with your password, and answer any questions asked of you. After installation KDE Partition Manager can be found in the Application Menu under Applications/System or by selecting the menu and typing its name.
Tips and tricks
I probably tend to use KDE Partition Manager more than most, or maybe not but here are some things to know that are helpful.
Growing a partition is a lot faster than shrinking or moving it. Basically anything where you have to move the first block of the partition you are better to copy all the info off, delete the partition and remake it at the smaller size or correct place and then refill it.
Backups and double checking are your friend. Once I went to change a partition and I must have brushed the pad with my thumb or something because although I checked everything was correct it was the wrong drive. Easy way to lose six months of stuff. Great way to learn how to use TestDisk (eg; very slowly and carefully) to recover data
Sometimes for you will find a partition that can't be wiped that you want to wipe such as a USB partition. Just rewrite the partition table and create a new partition. It is faster than trying to find out what Windows did this time.
If you are trying something, make an image first. That way if you break the partition you don't have to recover it.
Try and figure out the problem before jumping to conclusions. For instance, after installing my first Raspberry Pi my partition size was wrong and then it crashed. I thought the two things were connected and eventually gave it away. Later I found out that you had to manually expand to fill the partition and actually it had just been a bad SD card. But hey, someone else is happy. :) Have fun!