diff --git a/index.js b/index.js
index 4f327cc..0acd553 100644
--- a/index.js
+++ b/index.js
@@ -46,11 +46,11 @@ async function getAndPostPullRequests() {
       body: body,
       head: branch,
       base: base_branch,
-      assignee: assignee,
-      assignees: assigneesInput ? assigneesInput.split(",") : [],
-      labels: labelsInput ? labelsInput.split(",").map(Number) : [],
-      due_date: dueDate ? dueDate : null,
-      milestone: milestone ? parseInt(milestone, 10) : null,
+      assignee: assignee || undefined, // Changed to be omitted if empty
+      assignees: assigneesInput ? assigneesInput.split(",") : undefined, // Changed to be omitted if empty
+      labels: labelsInput ? labelsInput.split(",").map(Number) : undefined, // Changed to be omitted if empty
+      due_date: dueDate || undefined, // Changed to be omitted if empty
+      milestone: milestone ? parseInt(milestone, 10) : undefined, // Changed to be omitted if empty
     };
 
     // Perform the GET request to check if a similar PR exists