You can disable data on the account first (using the USSD codes above), then swap over to the new SIM card.mum got an sms from sinktel saying nid to upgrade her 2g sim to 4g sim n it's foc.
but tis sim is only for call/sms, n it's the safest sim card for her lol, coupled with tpg senior $5 plan.
n the site here says 2g sim won't work with "newer" 4g/5g phones. is this just another ploy to get ppl to kena data charges eating away their main acc balance?
https://www.singtel.com/personal/products-services/mobile/prepaid-plans/goodbye2g