How can I add Rich Text Excerpt to a recurring event?

I guess the Events manager plugin is storing data for recurring events in the postmeta table under a custom key (the excerpt is stored in the posts table under post_excerpt). In order to get the Events manager plugin to present a rich text editor for recurring events, the code which adds metaboxes / editors for recurring events would have to call wp_editor() like this plugin does instead of using a textarea. This may be problematic if the field is dynamically added (which I’m guessing is probably the case). In other words, it is possible that this cannot be achieved, and the feature would have to be added by the Events manager plugin author, or by you if there is an appropriate hook to call in the plugin.