You can actually just kill lvrt, which will then restart itself: i.e. "killall lvrt" from the shell. I do that all the time during development/debugging. Probably not practical for a deployed scenario though. When to you need to do this?
Note that if you have a deployed startup app (sounds like you do) lvrt will stop restarting itself after a couple rounds of this, on the theory that something is wrong with your app and you want to connect from the IDE to debug it. You can disable that behavior by setting YouOnlyLiveTwice to FALSE in /etc/natinst/share/ni-rt.ini's [Startup] section (which may not exist so you may have to add it). Disclaimer, this is an internal/debug setting that may move, change, etc. in the future without notice.