When a table or its settings have changed, the templates for that table have to be synced. If a new column is added to a table for example, the template needs to be updated to use the new column. If the column is not required, the template will continue to work. It will just not show the new column. If the column is required however, users will no longer be able to insert a new row for that table. This is when a template must be updated to prevent errors.
A reconciliation is a synchronization process which updates a template from new database definitions or plugin settings. Enable checkbox Keep options? if you wish to keep existing options (like labels, default where, etc.). Otherwise all options will be lost and set to their defaults.