need help shaping neck

All sizes: Shape neck: Next row: (RS). K1.
K2tog. Knit to last 4 (4-5-5-5-4) sts. Cast
off rem 4 (4-5-5-5-4) sts.
Rejoin yarn and purl 1 row.
Dec 1 st at neck edge on next and every
following alt row 3 (3-2-4-4-5) times
more, AT SAME TIME, dec 1 st at raglan
edge (as before) until there are 3 sts.

Above is the pattern. When it says to cast off and later to rejoin, am I cutting the yarn and rejoining it again? Very lost here. Thank you for your help.

I don’t think you’re lost at all, that’s exactly what I’m reading as well. Cast off your last 4 stitches, bind off, and rejoin at the beginning of the row to purl 1 row.

As a side note, it seems a bit extraneous to me to do that, but as I can’t see the rest of the pattern it might make more sense in context. Good luck!

Welcome to KH!
I agree, that certainly seems to be what the pattern is saying.
What pattern are you following? Can you give us a link or a pattern name?