knitting in round with multiple colors

I am knitting a cardigan sweater in the Icelandic design. The sweater is knitted in the round with two purl stitches where the sweater will be split (cut) before knitting the button band for the cardigan. The two stitches are in white the preceding and following stitches are in another color and are knitted. When knitting in the round the yarn for the purl stitches are at the end of the second purl stitch. How do I move the yarn so that it is in front of the first stitch. I cannot figure out the yarn mechanics. Someone please help.
Thank you

It seems to me that the white yarn is going to become part of the steek or cut. It may be there just to mark the cut line so you could just drag the yarn back behind or even in front of purl stitches one and two to work the next round.
Another choice since the white doesn’t sound like it’s used anywhere else in the round is to use the last color of the round in place of the white yarn and place a marker at the steek. You’ll have to be careful in cutting to make sure you cut up between the two purls but you can always mark that with pins once you get to that step.

Thank you. This is the first time I have tried to knit a cardigan in the round. I considered using the last color of the round. You are right I am cutting between the two purl stitches (after I have run two rows of machine stitches up the sweater in the pearl stitches). I will then cut between the two rows of machine stitching. Then I will knit the border which is white. I have tried it both ways (the white, with the yarn brought back to the start of the purls, results in a ridge with no clear identification stitches). and the continued color which is neater and will be easier to identify for stitching. What I was hoping for was a trick for placing the yarn. Thank you again. Carol