Is it possible to change or pivot the type of content for a website?

Yes, it is possible to change and pivot the content type of the website. But you have to think twice before doing it. As your website is already ranked on google for that particular and has a good position so why do you want to change the topic, you have already selected the niche for your website.
If you want to change it then you need to follow some tactics: Make it when you need to pivot the content type. Before doing it make sure that you always put your audience first. You need to change your content length according to your needs. Be ready to experiment with the content type. You can experiment with such changes to know better about your audience and how it is useful for your website.

Why pivot at all? Keep the content that obviously works for your site, and add more to cover additional keywords/topics.

Thanks for the replies.

The website basically only gets traffic each September, but wasn't as successful as I had hoped in terms of ads and affiliate offers.

I have experimented with some semi related content and have found that it ranks well on search engines, but not sure if it is worth pursuing.

The site gets over 100 thousand page views each September.

Changing the type of content may not work. For example, if a site is ranking with "seo" keyword and later we want to change the keyword to "flower", then it will not work as expected. Search engines make a profile of trust with a category. We can't change such category at randomly.

If the category is same then yes, we can target more relevant keywords by adding or modifying content of pages or adding more pages.