Select Quotation Style in the Quotes submenu of the Convert menu to choose which quotation characters are converted by all the other items in the Convert|Quotes submenu. The choices in the “straight to smart quotes” group are explained in the Convert|Quotes|Straight ⇒ Smart Quotes topic. The options in the “smart to straight quotes” group are explained in the Convert|Quotes|Smart ⇒ Straight Quotes topic. The “replace smart quotes” group is explained in the Convert|Quotes|Replace Smart Quotes topic.
Whenever you change settings in the Quotation Style dialog, those settings are used for all future quote conversions in all files until you change the settings again.