There's no script command for that. But you may try to execute corresponding command using "call" script command:
https://winscp.net/eng/docs/scriptcommand_call

Hi,

how can ich change the owner of a dirctory form root to mobile by script.

in my script i have following:

put private\var\mobile\Documents\www\ /private/var/mobile/Documents/

the folder www should be switched from owner root to mobile

thanks for help!