With Really Simple Systems CRM you can easily merge and copy Accounts.

In the Accounts page, select the Accounts you wish to copy or merge using the checkboxes on the left hand side of the table. With this action a new function button ‘More’ will appear¬†above the table. Clicking on this button will give you a dropdown list of the functions available i.e. ‘Copy’ and ‘Merge’. Simply click your selection and the account will be copied or merged as required.

CRM Accounts: Copy or Merge Duplicates in your CRM