How to Make a Member an SA of a group without an SA

I serve as an Admin for a group that currently doesn't have an SA.  How does one make a member an SA in such a group?  It seems that an Admin cannot do it.

1. Open a forum and propose new SAs. Everybody who wants can propose himself as candidates. 
2. The members may give their vote in the forum
3. After 3 days the result is given
4. Write to chess.com support and inform them
5. they make the winner SA

Thanks for the quick response.  Are there any restrictions about who can serve as SA --- it used to be that an SA had to be a premium member.  Is that still the case?

I assume yes.

But its also sufficient to be premium when you become SA. means: you can pay premium for 1 month, become SA and then stay in this role, even if your premium membership disappears after the month. 

Once SA you stay SA