Backing up and restoring your iPad/iPhone
If you delete join.me from your iPad or iPhone, you will also lose any existing whiteboards. You should backup your device to protect your data. By backing up regularly, you remain prepared should you need to restore data to a new device.
Follow these instructions from Apple to backup your device. Backups are for the device itself, not specific apps or data.
Follow these instructions from Apple to restore your device. Restoring a backup of your original iPad or iPhone using iTunes is the preferred method because your whiteboards and icon libraries will be restored to the new device.