We'll need to add the relevant info, and come up with an appropriate, but succint, title for it.
How do I give another user maintainership of my community?
If you no longer want to maintain a community, you will first need to work out an agreement with another member to transfer the community to them. Once a new maintainer has been chosen, go to the Community Management page (http://www.livejournal.com/community/manage.bml) and click the "Members" link. Here you can select the checkbox for the "Maintainer" status of the member you've chosen, and deselect the checkbox for your own "Maintainer" status. You will also need to give the community password to the new maintainer, at which time they may wish to change the password (http://www.livejournal.com/support/faqbrowse.bml?faqid=18).
You can use the same method to add a co-maintainer to your community. Follow the same process as described above, but don't deselect your own "Maintainer" checkbox. Once a member has been added as a co-maintainer, they will have the same maintainer privileges as you currently do.