How to migrate from Yoast

If you want to copy your meta descriptions from Yoast to post excerpt you can use SQL.

To compare excerpt and Yoast mesta description:

SELECT t1.ID, t1.post_title, t1.post_excerpt, t2.meta_key, t2.meta_value
FROM wp_posts AS t1 
	INNER JOIN wp_postmeta AS t2 ON t1.ID = t2.post_id
	WHERE t2.meta_key = '_yoast_wpseo_metadesc'

And to copy from Yoast to excerpt:

UPDATE wp_posts as t1 INNER JOIN wp_postmeta AS t2 ON t1.ID = t2.post_id
SET t1.post_excerpt = t2.meta_value
WHERE t2.meta_key = '_yoast_wpseo_metadesc'