How to send Magic SysRq keys to Linux hosts

[wonder-wanderer]

Hello, I need to be able to send magic sysrq to the host via the Mesh Commander remote desktop (while keep pressing left Alt key send the following keys: SysRq/PrntScrn, r, e, i, s, u, b -> more details https://en.wikipedia.org/wiki/Magic_SysRq_key)

How can I do that? It's required for Linux emergency system shutdown (as gracefull as possible, with unmounting filesystems and syncing disks) when something hangs in the system and normal CTRL-ALT-DEL doesn't work, in order to avoid just powering down, so that as much as possible we minimise the risk of data loss.