If I understand properly, you do not want to change the timezone which will remain TZ=Africa/Tripoli but you want to replace the file storing the timezone definition, here /usr/share/lib/zoneinfo/Africa/Tripoli, by a file containing a different definition, presumably built with the
zic command.
Assuming this is what you want to do, changes should affect
the existing and future processes time representation immediately, i.e. without requiring a reboot. However, this is unsupported and there is a risk for a Solaris patch to overwrite your customized timezone.