S.C. Code § 62-6-105
By a writing signed by all parties, the parties may designate as agent of all parties on an account a person other than a party. Unless the terms of an agency designation provide that the authority of the agent terminates on disability or incapacity of a party, the agent's authority survives disability and incapacity. The agent may act for a disabled or incapacitated party until the authority of the agent is terminated. Death of the sole party or last surviving party terminates the authority of an agent. The designated agent on an account is authorized to make all transactions on the account that the party can make, including, but not limited to, closing the account. An agent serving under a durable power of attorney can change, modify, or revoke an agent designated on an account.
S.C. Code § 62-6-105