Prawn: I want to ask: if the mobile phone is changed to a SIM card, is there a record of someone texting or calling the original number again?

If you change it in a short time, the text message is still there, but it won't be displayed when someone calls, unless you send a text message to inform you that your phone is turned off, but that will cost you. Generally speaking, SMS should be visible 24 hours after you switch back to your sim card. If you are afraid of someone calling the original number, you can set up call forwarding!