if 'SPANK' is coded as 'PSNAK', then how will 'THROW' be coded?

HTORW HTWOR HTWRO HTRWO

HTORW

The pattern is observed as follows: 1st letter exchanged by 2nd, 3rd letter is exhanged by 4th and last letter remains same. According to the pattern, THROW will be coded as "HTORW"