Realme
Enable or Disable a SIM Card auf Realme
On Realme phones running Realme UI, both SIM slots stay active by default once two cards are inserted. If you only need one line active, for example switching between a work and a private number, you can turn a SIM off in software instead of physically removing the card.
Deactivating a SIM card stops it from receiving calls, texts and mobile data. All active services, from call forwarding to data usage, then run entirely through the remaining SIM as if the phone only had one card installed. Nothing on the deactivated SIM is deleted, so you can switch it back on anytime without re-entering settings.
Where to enable or disable a SIM
Go to Tap on Settings ➔ Tap on SIM card & mobile data ➔ Choose a SIM card (Dual SIM) ➔ Enable or disable the SIM card. Select the SIM slot you want to change and toggle it off or back on.
This is useful when a SIM causes signal issues, drains battery in a weak coverage area, or when you simply want to pause one number temporarily. If you need to swap a physical card instead, powering off the phone before ejecting the tray is the safer option.