One way of doing it:
- go to the track
- make a time selection (drag with your left mouse)
- right click in the time selection and choose 'Split items at time selection' (SHIFT S does the same)
- delete the part that you want to get rid of
- drag the right part towards the left part until they click together
- select both parts, then right click and choose 'Glue items'
- press ESC to remove the time selection