The famous developer Eric Marciano have brought airliners systems and utilities for FS for many years.
In 2013, he launches Easy FMC. It can be installed on any aircraft panel of your choice in FSX and FS2004. It uses the default navigation database, and is inserted with a dedicated utility so you don’t have to edit manually any panel.cfg. In flight, create your flight plan from scratch, add or delete waypoints, use the “direct to” waypoint to skip a planned waypoint.