The standard user or a member of the community can always leave the community they are part of at any point in time from their profile section.
Profile>> Communities>> Your Communities
Click on the "Leave" link to discontinue your membership in the particular community. A dialog box will appear to confirm your action.
Once deletion is confirmed you will no longer be part of the specific community.
Please Note: Leaving the community will only remove your membership. All your submission and identity details will be stored in the IdeaScale database.
The moment the member leaves the community the administrator of the community is notified via an email notification.
The member can choose to rejoin the community, by logging into the community with the community url, however all of his submission will now show as Submitted by Forgotten Member. Basically the member will start as a new member in the community.