How to convert from 2 needle knit to loom knit

First you need to change all the purls to knit, and all the knits to purls.
Then, if there is no knit across rows between rows, then you need to read every other row right to left:

1st row left to right, next row right to left.

kpkpkp-----> 1st row
pkpkpk <--------2nd row etc.
If there is a row knit across between rows, the just read it as is.

If you are reading from a chart, then read 1st row right to left, then second row left to right.

kpkpkpkp-------->2nd row etc.
pkpkpkpk<------- 1st row