In the Navigation pane, select the Records tab
Double-click a client to display the list of matters within it. Alternatively, select the client and press the Enter key.

In the List pane, right-click the matter to be moved.

From the Action menu in the toolbar, select Move.

Alternatively, right-click the particular matter, and then select Move. The Move Matters dialog opens. 

Update the following fields:

• Destination Client: Select the  icon and select the appropriate client to which you want to move the matter.

• Matter ID Override: Provide a new ID if you want to change the existing ID.

Select Process > Close.