“Resolve” is the last sixth tab in “Starship Equipment” window. Here you can resolve those parts of the equipment, that you no longer need. As a result, this equipment will be destroyed and you get the items that can be applied later to upgrade, reform, raise and create other piece of your fleets equipment.
Destroying the equipment you get back 80% of the materials spent for their improvement before.
Use the drop down menu to sort the equipment by type.