We prevent ASINs from being in more than one goal to ensure each campaign performs at optimal levels.
So, if you have an ASIN already in a goal that you wish to move to another goal, you must remove the ASIN first or delete the existing goal entirely.
To remove an ASIN from a goal
Select the goal that contains the ASIN you wish to remove.
Click on Edit Product and deselect the ASIN you want to remove.
Then click Update in the configuration panel on the right.
Alternatively, you can also delete the ASIN from the goal to remove it by clicking on the trash bin icon.
Lastly, deleting a goal will also make the ASIN available to be added to other goals.
To delete a goal, follow the instructions here.