The below post will mention steps about how to update PAN in the UAN Portal
Step 1 : Login into the Portal
Step 2 : Click on Manage
Step 3: And the Click on KYC link under Manage menu
Step 4: Then Click on the CheckBox for PAN
Step 5: Update your PAN Number and Name on PAN Card
Step 6: Click on Save
Step 7: Once you Click on Save, you will see the Aadhaar under Pending KYC verification
Once Saved you will get it under Pending KYC or it will be directly approved