Delete/Remove Customer field from Case Entity

We cannot remove the Customer field from the Case Entity. 

There a no way to remove the Customer field from the Case Entity. The customer field is a system field,We can use following workaround to fix the issue. 

1. Hide the customer field.

2. Add a new Contact and Account fields to the case screen

3. Populate hidden Customer field using JavaScript to the new Contact/Account field or use business rule to set customer lookup.

 // JavaScript 

var customername = "A. Datum";
(Xrm.Page.getControl("header_process_customer").getAttribute()).setRequiredLevel("none");

var object = new Array();
object[0] = new Object();
object[0].id = "475b158c-541c-e511-80d3-3863bb347ba8";
object[0].name = customername;
object[0].entityType = "account";
Xrm.Page.getControl("header_process_customer").getAttribute().setValue(object);
Xrm.Page.getControl("header_process_customer").setVisible(false);

Business Rule:

Hope this helps.