Turn off swap. Resize (e.g. 8 Gb). Make swap usable, Activate swap
sudo swapoff -a
sudo dd if=/dev/zero of=/swapfile bs=1G count=8
edits: (thanks @joekamprad )
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile
Edits: source of info I found
https://arcolinux.com/how-to-increase-the-size-of-your-swapfile/
Just tested, works like a charm.