Moving items from one store to another in SixBit is a two-step process. First, you need to create a new Profile in SixBit through the Application Menu (little orange guy (or the File button in the top left), top left corner of SixBit) | Manage | Profiles window.
Once set up and authorized, you can then update your items in bulk to set the new Profile through the Batch Change window, or manually by opening a single item in Sell Items mode, Organization tab. Once the Profile is set on the item you can then submit the item to eBay within SixBit and it will list to the newly added Profile. In the case where the item has profile-specific information applied to it already (for example, store categories, and seller account specific shipping presets), that information will be removed from the item, since it does not apply to the selected profile. For this reason, we can recommend making a batch change definition to change these fields at the same time.
The following link to the User's Guide provides more information about Creating a Profile: https://www.sixbitsoftware.com/EN/Creating_a_Profile.htm
The following link to the User's Guide provides more information about Updating the Profile in the Item Window: https://www.sixbitsoftware.com/EN/Adding_a_Profile_to_an_Item.htm