If you have the Reserve card, you can have additional card holders on your account. The Delta Platinum card is free for additional card holders, and the Delta Reserve card is $175 for EACH additional card holder that you want to have a card. All points/miles/MQDs accrue to the primary card holder. If the additional card holder has the Reserve card, they can then get into the SC for free traveling alone. Otherwise as mentioned, if they are traveling with you, you can use a guest pass or pay for their entry. Additionally, if you reach Diamond status, you can elect the add-on SC Executive pass as a part of your Diamond Choice Benefits.