If you use different coloured skeins for socks the change from one colour to the other can look very abrupt also when using colour changing yarns.
She presents here softer colour blends in striped socks by slowly knitting more rounds of the old and less rounds of the new colour.
If necessary you can also use the previously presented jogless stripes knitting :)
Links:
Colour Blends in Striped Socks (Peter Piper, Blended)
via: Blender Socks
Here at unikatissima:
Jogless Stripes Knitting