A distribution list has 2 different status: Active or Inactive.
A new distribution list record is set to Active as default.
To set the status to Inactive click on the Deactivate option under the Workflow menu. When the status is inactive, changes to the distribution list are not allowed and the distribution list is not selectable in a consultation record anymore.
Use the Reactivate option available under the Workflow menu to set it back to active.