updated sms chat docs

Author: ramsrib

fern/chat/sms-chat.mdx

@@ -84,19 +84,10 @@ sequenceDiagram
 
 SMS conversations use automatic session management:
 
-<Tabs>
-  <Tab title="Automatic Behavior">
-    * **New customers**: Get a fresh session on first text
-    * **Returning customers**: Continue existing session if under 24 hours
-    * **Session expiry**: After 24 hours, new session created automatically
-    * **Context preservation**: Full conversation history maintained within session
-  </Tab>
-  <Tab title="Manual Management">
-    You cannot manually manage SMS sessions - they're handled automatically by Vapi's SMS infrastructure.
-    
-    For programmatic chat with manual session control, use the [Chat API](/chat/quickstart) directly.
-  </Tab>
-</Tabs>
+* **New customers**: Get a fresh session on first text
+* **Returning customers**: Continue existing session if under 24 hours
+* **Session expiry**: After 24 hours, new session created automatically
+* **Context preservation**: Full conversation history maintained within session
 
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