diff --git a/erpnext/support/doctype/service_level_agreement/service_level_agreement.json b/erpnext/support/doctype/service_level_agreement/service_level_agreement.json
index 61ca3a3..de3389a 100644
--- a/erpnext/support/doctype/service_level_agreement/service_level_agreement.json
+++ b/erpnext/support/doctype/service_level_agreement/service_level_agreement.json
@@ -150,7 +150,8 @@
    "fieldtype": "Link",
    "label": "Document Type",
    "options": "DocType",
-   "reqd": 1
+   "reqd": 1,
+   "set_only_once": 1
   },
   {
    "default": "1",
@@ -178,7 +179,7 @@
   }
  ],
  "links": [],
- "modified": "2021-05-29 13:35:41.956849",
+ "modified": "2021-07-08 12:28:46.283334",
  "modified_by": "Administrator",
  "module": "Support",
  "name": "Service Level Agreement",
diff --git a/erpnext/support/doctype/service_level_agreement/test_service_level_agreement.py b/erpnext/support/doctype/service_level_agreement/test_service_level_agreement.py
index 0d20b98..7c18a65 100644
--- a/erpnext/support/doctype/service_level_agreement/test_service_level_agreement.py
+++ b/erpnext/support/doctype/service_level_agreement/test_service_level_agreement.py
@@ -328,16 +328,11 @@
 			"entity": entity
 		})
 
-	service_level_agreement_exists = frappe.db.exists("Service Level Agreement", filters)
+	sla = frappe.db.exists("Service Level Agreement", filters)
+	if sla:
+		frappe.delete_doc("Service Level Agreement", sla, force=1)
 
-	if not service_level_agreement_exists:
-		doc = frappe.get_doc(service_level_agreement).insert(ignore_permissions=True)
-	else:
-		doc = frappe.get_doc("Service Level Agreement", service_level_agreement_exists)
-		doc.update(service_level_agreement)
-		doc.save()
-
-	return doc
+	return frappe.get_doc(service_level_agreement).insert(ignore_permissions=True)
 
 
 def create_customer():