The resheathing tool includes a flexible tubular body with a wall, an inner bore, and an aperture formed in the wall. The tool can be used to facilitate the unsheathing of the vasoocclusive device from the reloadable slotted introducer sheath by threading a proximal portion of the sheath out the aperture of the tool while sliding the vasoocclusive device distally through the sheath. The tool facilitates resheathing of the vasoocclusive device by introducing the vasoocclusive device through the slot of a reloadable slotted introducer sheath into the sheath by threading the reloadable slotted introducer sheath through the aperture and into the inner bore of the tool while threading the vasoocclusive device through the inner bore of the tool. At the same time, the resheathing tool prevents the elongated vasoocclusive device from moving out of the reloadable slotted introducer sheath through the slot.