What does this mean?

Hi this is my first post and this instruction has completely foxed me. Anybody shed some light on what it means? Thanks. ‘Neckband - work in stst for 3,5 cms then work several rows in stst in a different colour. Simply unravel to base colour when making up’

What is the name of your pattern?
I wonder if this is a way of holding live sts instead of placing them on scrap yarn. The directions for making up may help figure this out.
Since it’s worked in stockinette stitch, it’s going to curl unless there is something else to be worked at the collar (maybe a hood?).

It’s Axelle sweater (blue short sleeved T shirt) from knitting bee. The neck in the picture shows it curled anyway

https://www.knitting-bee.com/free-knitting-patterns/free-tops-knitting-patterns/free-knitting-pattern-for-an-axelle-sweater-in-phildar

It seems that the directions to continue with scrap yarn are just a way to hold the live main yarn sts. You could equally well put the sts on scrap yarn or even bind them off loosely. The making up directions are to stitch the neckband to the sweater body on the right side in order to maintain the roll.

“Sew neckband, matching sts and using backstitch on right side of work”

Thank you so much, now I understand!