Where have my parrots flown to?

Hi Hamarriet, welcome to GOY, as the plant is otherwise healthy, i would assume this is due to time of year. i must admit, i have no experience with this particular variety, but i do know Impatiens, in general flower through the summer. most varieties are purely grown as annuals. but if you are overwintering inside, or using as a house plant, i would saggest letting it have a bit of a break, this is beneficial to all flowering plants, be careful not to overwater, keep it away from drafts and central heating, then start feeding and maybe re-pot or top dress the soil about March time, and this should bring it back into flower for you.