The device cannot be shipped with a cartridge installed, so it will need to be removed. 
You will want to engage the device and drain the cartridge by pressing the red Activator Button until the gas ceases to flow from the Luer exit. As an additional caution, please always wrap the cartridge with a towel when removing it; and always point the cartridge toward the floor when removing. 
Cartridges can get very cold and/or become a projectile if gas remains in them and they are removed. 
Wrap the device carefully in bubble wrap to prevent further damage and ship it back in its original caseusing the label you were provided, or by using your own FEDEX or UPS shipping label.

Ship the Device to:
AngioAdvancements Customer Service
5235 Ramsey Way #11
Fort Myers FL 33907