In order to remove any promotion from the group, you will find the option next to each promotion on the list. Click on the icon and the promotion will disappear from the group of promotions and you will return to the section 'Promotions you can add'.
Note: The promotion set as the Group's master promotion cannot be removed from the Group, and in this case, you will notice that the option to delete is not included in the list of promotions. In order to remove it, you must first define another promotion as master from the "Settings" section:
Once the Group's master promotion has been changed, you can remove the promotion from the Group.