The server setting is entered by default. It is based off the server information you entered the first time you accessed Agenda To Go. You can only change the server location if you are not logged in to Agenda To Go. If you do change the server, a message is displayed indicating that if you change servers, you will lose all the data on your device.
If you are certain that you want to delete the data contained on the current server, tap Confirm. Keep in mind, if you change servers and delete the data, you are deleting all data related to the current server and you will not be able to retrieve it, so make sure that this is the action you want to take.