Changing FPP question

I see that people are changing FPP reservations and finding attractions with by looking for 1 or 2 reservations at a time. I have a party of 7. If I try to change it for 1 or 2, will I lose out on my current FPP as it looks for a new one? How do I do this? I see that I can change times for 1 or 2 and then change attraction. Is this the best way?