Select Clients from the toolbar at the top of the site.

Along the left side, check the first clients' box that you want to merge.

Once you select the second client, you will see Merge Clients light up in the top right.

Once you click on Merge Clients, you will then be taken to a screen where you will choose which client info you want to carry over to the merged client.

Click on Merge Clients in the bottom right to confirm the merge of the client profiles.