changing arduino yun configurations of Arduino Yun

I have already configured my ArduinoYun for using it at my home. A sketch is already uploaded. Tomorrow I will need to connect to a different WiFi. So my question is that :

1) I will need to reset my Arduino, then connect to Arduino-YUN-XXXX from my PC and configure that again with the new network, right? is there any other way? 2) If I need to do that, will I need to upload again my sketch? Is there a way of not having to upload it again? Imagine I want to give Arduino to a friend of mine, who does not have any idea of how Arduino works.

Thanks in advance.

Yes, start up the Yun, and wait for it to fully boot up. Then press and hold the WLAN RST button for 5 seconds. That should cause the Yun to go back to the WiFi access point mode. After it finishes rebooting, you should be able to connect to the Yun again like you did when you first set it up.

This should not affect the sketch, it should keep running.

One potential issue is that if the sketch is running when you reset the WiFi settings, and it is sending data to the Linux side at just the wrong time, it could interrupt the rebooting of the Yun. If that happens to you, and the Yun doesn't come back after pressing the WLAN RST button, try cycling power on it.