How to resize casper-rw from live CD?

Situation: Ubuntu booted from a live USB drive (specifically made with YUMI).

It has a persistent storage partition which is filled up. I'd like to increase said storage partition's size without losing data in the process.

How can this be done either through YUMI itself or through some other process, preferably Windows-based temporarily since I can't run gparted on the live USB while it is running?

Using YUMI add a second of the same ubuntu (if have space, other way use another drive...) you will need change a least one letter to the ISO name so YUMI don't get in conflict, setup the new casper size as desired, remembering FAT32 doesn't allow files bigger than 4GB (YUMI wouldn't allowed it anyway)... Then do the following:

https://askubuntu.com/questions/1082439/how-to-increase-persistent-file-size

You can see others posts about it at the YUMI site, the "How to resize casper-rw Images in Windows" one could be what you need:

https://www.pendrivelinux.com/tag/resize-casper-rw/

REMEMBER: Backup your original casper file prior manipulating it...