[Payment due @mkhutornyi] Allow clearing the Default Vendor by re-selecting it (CC/DC export only)

src/pages/workspace/accounting/intacct/export/DynamicSageIntacctDefaultVendorPage.tsx

@@ -30,6 +30,9 @@ import {useRoute} from '@react-navigation/native';
 import React, {useCallback, useMemo} from 'react';
 import {View} from 'react-native';
 
+// Sage Intacct's default-vendor fields hold a raw vendor ID; sending this empty string clears the default.
+const CLEAR_DEFAULT_VENDOR = '';
+
 function DynamicSageIntacctDefaultVendorPage() {
     const styles = useThemeStyles();
     const {translate} = useLocalize();
@@ -75,14 +78,21 @@ function DynamicSageIntacctDefaultVendorPage() {
         [translate, styles.pb2, styles.ph5, styles.pb5, styles.textNormal, isReimbursable],
     );
 
+    // Only the non-reimbursable credit-card-charge path treats a blank vendor as a valid state (falls back to "Credit Card Misc"), so we only allow clearing when that setting is active.
+    const canClearByReSelecting = settingName === CONST.SAGE_INTACCT_CONFIG.NON_REIMBURSABLE_CREDIT_CARD_VENDOR;
+
     const updateDefaultVendor = useCallback(
         ({value}: SelectorType) => {
-            if (value !== defaultVendor) {
+            if (value === defaultVendor) {
+                if (canClearByReSelecting) {
+                    updateSageIntacctDefaultVendor(policyID, settingName, CLEAR_DEFAULT_VENDOR, defaultVendor);
+                }
+            } else {
                 updateSageIntacctDefaultVendor(policyID, settingName, value, defaultVendor);
             }
             goBack();
         },
-        [defaultVendor, policyID, settingName, goBack],
+        [defaultVendor, policyID, settingName, goBack, canClearByReSelecting],
     );
 
     const listEmptyContent = useMemo(

src/pages/workspace/accounting/qbo/export/QuickbooksNonReimbursableVendorSelectPage.tsx

@@ -58,8 +58,15 @@ function QuickbooksNonReimbursableVendorSelectPage({policy, configKey, updateVen
             isSelected: vendor.id === currentVendor,
         })) ?? [];
 
+    // Only the CC/DC export path treats a blank vendor as a valid state (falls back to "Credit Card Misc"), so we only allow clearing on that configKey.
+    const canClearByReSelecting = configKey === CONST.QUICKBOOKS_CONFIG.NON_REIMBURSABLE_CREDIT_CARD_DEFAULT_VENDOR;
+
     const selectVendor = (row: CardListItem) => {
-        if (row.value !== currentVendor) {
+        if (row.value === currentVendor) {
+            if (canClearByReSelecting) {
+                updateVendor(policyID, CONST.INTEGRATION_ENTITY_MAP_TYPES.NONE, currentVendor);
+            }
+        } else {
             updateVendor(policyID, row.value, currentVendor);
         }
         Navigation.goBack();