You can’t permanently change the center point. The best you can do is to use the Rotate Tool (R) to move a center point for rotation, but after the you’re done with the tool the object will hold it’s original center.
Here’s something about using the rotate tool… https://library.creativecow.net/tutorials/adobeillustrator#rosati_vincent
You could also group your object with a large empty square. Where you would position the main object’s desired center-point to the center of the enclosing square…
Of course, you would not use the dotted line in your version. The stroke would be empty.