Is it permissible to exchange twenty dinars from zakah funds for twenty dinars from voluntary charity funds, and to give them in charity to relatives?

The questioner : I was in Kuwait in a department that handled both zakah and voluntary charity. I had zakah to pay, so I deposited my zakah in the zakah bank and took some from the voluntary charity for my aunt. Is this permissible?

The Shaykh : Where did you put your money?

The questioner : For example, I had twenty dinars written down as my zakah obligation. I put them in the zakah bank and took twenty dinars from the voluntary charity.

The Shaykh : What do you mean by "zakah bank"?

The questioner : ... .

The Shaykh : Yes.
The student : ... .

The questioner : No, no. I was at the mosque. There were zakah funds and there were voluntary charity funds. I put twenty dinars of my own into the zakah collection and took twenty dinars and gave them to my aunt. Is this correct?

The Shaykh : Where did you take the twenty from?

The questioner : From the voluntary charity, or I exchanged them, meaning I swapped them.

The Shaykh : How? I don't understand. How did you put in twenty and take out twenty? How?
The student : I had twenty dinars of zakah. I put them with the zakah funds and took from the voluntary charity funds the same amount I had put in.
Another student: He had twenty dinars that he was giving as zakah on his wealth, so he went and put these twenty in the zakah box.

The Shaykh : Is it not yours?
The student : No, it is mine.
Another student: It is yours.

The Shaykh : You... let us understand this properly.
The student : ... .

The Shaykh : You gave twenty dinars from your zakah.
The student : Yes.

The Shaykh : To whom? To the zakah bank? Okay, who received the twenty dinars? An employee there?
The student : No, I am an employee at the mosque, and we were collecting voluntary charity.

The Shaykh : So you are an employee. You yourself put twenty dinars in the box, and you are an employee, and you took from the same box.
The student : From the voluntary charity, not...

The Shaykh : You took from the voluntary charity box.
The student : Twenty dinars.

The Shaykh : Just that. Okay, are you authorized for this matter?
The student : But I am the person in charge. I am the one who gives out the money there.

The Shaykh : That is the meaning of my question. Are you authorized? I mean, are you tasked with this?
The student : Were you responsible for this operation, overseeing this?
Another student: A deputy, I mean.
The student : A responsible deputy.

The Shaykh : Yes, the person in charge above you permits you to do this.
The student : He authorized you for this.
Another student: No, I mean, it is just that he...
The student : Okay, Shaykh, a question.
Another student: Here, Shaykh, we have not agreed.
The student : The offer.

The Shaykh : We are with you until you agree.
The student : About the food.
Another student: Both, both tomorrow.

The Shaykh : I mean, Hazim?
The student : ... .

The Shaykh : Are you with him?
The student : By Allah, if Allah wills, if I am late, I will meet with him.

The Shaykh : You are in a field where you get delayed, I mean.
The student : There is a possibility, if Allah wills.
Another student: I mean, the company does not allow it. The leave has ended.
Another student: Work is on Saturday, Shaykh.