Adding soil to raised bed with existing plants. Newbie question.

I’m in the Phoenix, AZ, USA area, in Zone 9b (or 10a depending on where I look). We built our first raised garden bed a year ago and have had mostly luck for total newbies. Our soil level is quite a bit lower than it was a year ago, and we want to raise the soil level again. Our concern, some of the existing plants currently in the garden we want to keep, and hopefully not disrupt. I probably want to keep half of these and add tomatoes and peppers like we had last spring. What’s the best way? Do I need to remove and replant after adding soil?