Can I change the sitemap change frequency?

This is an optional sitemap field to describe how often a URL is likely to be updated.

Yoast SEO no longer uses the frequency field in the XML sitemap and was removed from Yoast SEO v3.5. Google has said publicly that they don’t use them on most sites, and as such, the relevant optional field was removed from the Yoast SEO generated XML sitemap. You can also find out the Googler John Mueller confirming this on the Google Webmaster Central. 

You won’t need to change or add the frequency/priority in the XML sitemap as Yoast SEO automatically pings search engine crawlers as soon as you update or publish a page on your site. So, if you update a page frequently, Google crawlers should automatically be aware of the relevant changes at the right time.

If you need to add the frequency/priority to the XML sitemap, it will require development by adding filters or code customization.