Decreasing in Irish moss stitch

Hi, I need to decrease one stitch every row for 4 rows on neck edge in moss stitch. I’m finding when I do this it throws the pattern out. Any suggestions on how to do this at end of one row and beginning of next would be appreciated. Many thanks.
Carole

Welcome to the forum!
Usually this works out fairly easily for a decrease at the end of a row. The problem is how to pick up the pattern at the beginning of the row.
You can take the decreased stitch into account when you read the pattern and work out what the next stitch should be or there’s an even easier solution. Look at the row below and read your knitting.
So make your decrease which will throw off the pattern but then look to the stitches on the left needle (the stitches from the row below). Use those stitches to determine how to work the next stitch of the current row. If the row below the next stitch was a knit then you can decide if the next stitch on the current row should be worked as a knit or a purl.

See if this video helps (see especially 11:40 min for seed stitch). It’s similar to the way to work moss.