You can, but not by design!
Each section has a wrap of teflon tape around them about 20cm from the bottom. This acts as a stop on the section. To remove a section you will need to undo the clamp of the section you wish to remove. This will allow the section and tape to slide out, now you can remove the tape. You can then re-assemble the clamp on the section and simply slide the section in or out whenever you need to.
What some users have done is to replace the tape with a painted or permanent marker line so that they know when to stop extending the section.