Horizontal alignment

Redefine complex could work, however rather sketchy depending on the need and corridor references.  Any changes will shift stationing previously applied either way.  You can also try to cycle through the base elements of the original linework (via right-click) and possibly reduce those segments to such a small amount they don't affect the begin/end stations.  Understanding what you're goal is by removing those will help offer a solution.  Since any significant changes to the alignment affect any corridor objects based on stationing, you may want to drop down to original elements and re-complex as desired. 

Hi John,

Something not very publicised is that you can use to edit Geometry is use of the Microstation Vertex tools. Try just using the Microstation delete Vertex tool to delete the first and last points of the Geometry and that should do what you need.

Great guys, I'll consider both of these answers. Thanks for the help!