Sure.   Just decide the configuration changes you require and make them to the configuration, assuming you are a configuration owner.   Since this is the site admin forum, not list admin forum, you are.

There may be an additional step. 

For example, my announcement lists use the technique of having "Send= Private" (postings from subscribers only), with all subscribers having "nopost" as a subscription attribute.  For new lists, this means I configure with "Default-Options= nopost".  I put this into the configuration for new subscriptions, but with an existing list there is an additional step:  set all current subscribers to "nopost".   For this, I use the command "quiet set <listname> nopost for *@*".

Then I simply change the subscription of anyone I want authorized to post to remove the "nopost" attribute.      I prefer this method for reasons which include

• managing who can post does not require changing the list configuration
• It at least gives the list owners a chance at ensuring a poster is subscribed, thus having a chance to see posts before and after their post.
• It separates posting from subscription management.