Programming? Still clicking, time to time... But the first time, I was typing some very simple BASIC code on C64 from the user guide and a question popped in m

Programming? Still clicking, time to time... But the first time, I was typing some very simple BASIC code on C64 from the user guide and a question popped in my brain: is it possible to change a program when it's running? I was already a kid like to tinkering with basic electronics and mechanics but after this significant moment they started to decline steadily day by day and I put most of my time and energy to the programming. Software development, another story...