Doro phone from Argos (SIM free)

Hello
I need to get my elderly mother a new handset, she likes the Doro phone and they are available in Argos as SIM free units, just want to make sure that its as simple as swapping her over of her existing SIM (Vodafone PAYG) to the new handset? Any advice welcome, thanks

yes that simple

Thanks Frank, worked a treat, she is delighted with her new more 'senior' friendly phone!