It's hard to picture what you are doing so there might be a better way then this.
Open the 3D Sketch you want to move from the loft.
In that 3D sketch, draw a centerline perpendicular to the plane that is moving the part. You can click the centerline and the plane (or face of the part) and make a perpendicular relation.
Highlight all the sketch entities of the 3D sketch and click "move entities".
Uncheck keep relations.
Seltect the centerline you created and type in the distance of the move.
Restablish relations if you like or fix the geometry depending on what you are doing
You can always move the loft has a whole if you uncheck merge and use the feature move/copy body.
Like I said, it's hard to picture what you are doing, post an image?
If there is a single sketch then you may Right click on the sketch , then select Edit Sketch Plane. In property manager you will see the existing sketch plane. Delet this plane and select the plane onwhich you want to locate the sketch.