#83dd17 hex color code information, schemes, description and conversion in RGB, HSL, HSV, CMYK, etc.

1) Stop the container (you can do it from the proxmox web interface but considering that you will need ssh access to the server the complete the other steps, I have stopped the container using a simple command issued on the linux shell prompt):
pct stop container-id

2) Create a full container backup (to preserve the actual information within the container):
vzdump container-id -storage local -compress lzo

3) Destroy the container
pct destroy container-id

4) Restore the container from the previous created backup
pct restore container-id /var/lib/vz/dump/vzdump-lxc-container-id-2017_02_13-16_50_29.tar.lzo --rootfs local-lvm:25

Some infos about step 4:
The default backup location is /var/lib/vz/dump
When you create a backup using vzdump the file structure for the backup is: vzdump-lxc-container-id–year_month_day–hour_minutes_seconds.tar.lzo
local-lvm represents the name (description) of the local storage volume as shown in the proxmox web interface (Storage View); depending of your configuration, the name is probably different