If you want to change the order of clients within your deal, first step is going to Edit Deal (pen icon), from Deal View.
Next to every client, you have a delete button. Once you click on recycle bin icon next to 1st client in your deal and confirm the delete, then the secondary client will become first (primary client).
Lastly, to bring back the removed client, click on “Add another contact” button, and in field 'First name' type the client's name and pick them from drop-down menu.
This way you'll bring back the client you have previously deleted, without creating their duplicate.
If you've accidentally created a duplicate contact in this process, kindly check our article on How to safely remove duplicate contacts from system.
When you re-add the removed client, all their personal details will auto-populate in the deal, however their Income, Expenses, Assets & Liabilities will have to be re-added and relinked manually.