From now on, you can use two micro sd card with this Dual Micro SD Card Adapter
Not only for Raspberry Pi but also for other device
Convenient for using two Rasbpeberry Pi OS
Know more about this item, please click: https://www.raspberrypiwiki.com/index.php/Dual_Micro_SD_Card_Adapter
Please toogle to another card via switch after your turn off your device.
10 x Dual Micro SD Card Adapter