谢谢，不用了。

Use this when someone offers you more tea or a plastic bag. You can say it as one continuous thought. Keep your tone soft to remain polite. A small nod of the head helps convey sincerity. It works for physical objects and offered services. If a waiter offers a menu you already have, use this. If a friend offers a ride you don't need, use this.

Use it in shops when declined a receipt or bag. Use it at dinner when your host offers a third helping. It is perfect for street vendors who are a bit too pushy. It works well in professional settings when offered a coffee. Basically, use it whenever 'No' feels too blunt. It keeps the social harmony intact while getting your point across.

Don't use it if you actually want the thing! Chinese politeness sometimes involves 'refusing' three times before accepting. However, 不用了 is quite firm. If you use it, people will likely stop offering. Avoid using it with very close family for small things. In those cases, a simple 不用 (No need) is more natural. Don't use it if someone is offering help in an emergency.

Chinese culture values 'Mianzi' or face. Saying a flat 'No' can feel like a rejection of the person. Adding 谢谢 cushions the blow significantly. The 了 at the end is a change-of-state particle. It implies 'I am okay now' or 'No need anymore.' It makes the refusal feel less like a rule and more like a current status. It is the ultimate social lubricant for daily interactions.

• 不用，谢谢 (No need, thanks) - Flips the order.
• 不用了，谢谢你 (No need, thank you) - Slightly more personal.
• 太客气了，不用了 (You are too kind, no need) - Very polite for gifts.
• 真的不用了 (Really no need) - Use this if they persist.