Every Client profile has the remove button. Press it to remove the client and contact details from all Orders, Sales, and Leads. You still will be able to see the client data in your Order profiles, Sales profiles, and transactions, but you will no longer be able to modify it.

For instance, if you remove the client and then open the order or sale associated with the client, the system will notify you that the client no longer exists in the client base.

You can restore a deleted client in the Activity log report.

Generate a report for the event "Client deleted". Find the deleted client and click the Restore button.

Please note that deleted suppliers can be restored the same way.