Why there is no set_position_body?

Hi

While controlling the drone with off-board mode, I can only set Position in local NED coordinates, while velocity can be set both in local NED and body coordinates.
How come I can’t set position relative to the body frame?

If for say I want to get 5m higher from where the drone now, or get 10m forward regardless of postion and yaw, how can I do it?

Thank you