This task requires permissions that are found in all default marketing security roles Defined sets of privileges.The security role assigned to a user determines which tasks the user can perform and which parts of the user interface the user can view. All users must be assigned at least one security role in order to access the system.. More information about specific permissions and performing this task while offline: Marketing Permissions
In the Navigation Pane, click Marketing or Sales, and then click Marketing Lists.
From the list, select the marketing list that contains the accounts, contacts, or leads that you want to merge into another marketing list.
On the Actions toolbar, on the More Actions menu, click Copy to.
In the Look Up Records dialog box, select the marketing list you want to merge members into, and then click OK.