"Representative" means a person empowered to act for another, including an agent, an officer of a corporation or association, and a trustee, executor, or administrator of an estate.

“代表”指获得授权，代表另一方行事的人，包括代理人、公司或协会的高管人员以及遗产的受信托人、执行人或者管理人。

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One of the SLATs could have a third person act as co-trustee with the beneficiary spouse.

FORBES: Spousal Lifetime Access Trusts--Use Your Gift Tax Exemption Without Giving It All Away

When you are a trustee you are held to a standard of a fiduciary which means you must act in the best interest of the beneficiaries.

FORBES: Think Twice Before Becoming a Co-trustee of a Family Trust