Half in-the-round, half not!

hello everyone…longtime fan, first time poster, from Toronto, ON. I checked this section in hopes of avoiding a question that’s already been asked so I hope I’m not annoying anyone…
Making my first sweater, a relatively easy pattern from Suss Cousins (the tweedy cowl neck from Suss Design Essentials). In an attempt to keep my seaming to a minimum, I knit the bottom to underarms in the round. I am now working away on the back (back and forth on circulars), and pretty darn proud of myself…
Was, that is, until it occurred to me that I have no idea how to get the rest of my stitches “live” again once I start to work the other side of the garment. I will have bound off the cowl neck on the front, and there goes my live yarn.
Please help!

Once you’re finished with the back, knit the front the same way, just start with a new strand of yarn.

Assuming you put the other half of the stitches on a holder, it is simply a case of putting them back on a needle and then starting knitting with a new piece of yarn. Just hold the yarn with a few inches of tail hanging off to the side (to weave in later) and starting knitting with your yarn as if it was already attached. It may be a bit loose for a few stitches but you can tighten it up later or as you go along.