If you mean remove it from the timeline ... make sure ripple edits are enabled. Drag the cursor across the timeline where there is no event, either on a different track or beneath the tracks, to highlight the section you want to remove. Press the Delete key.

If you have lots of events filling up your track and have a hard time finding a place to drag, place the cursor at the beginning of the section you want to remove and press i, then at the end of the section and press o, then press Delete.

If you're taking about physically removing a section from a video file then perform the above and render to a new file.