Keywords are used by Google to determine the context of your webpage. Changing your target keyword informs Google that the page's context has changed. As a result, changing your target keyword will negatively affect your SEO for the original keyword you targeted while improving your SEO for the new keyword.
The hard work and money you have spent on your previous SEO campaign will be lost if you start a new campaign with a different keyword term. This is why:
A new set of keywords will need to be researched.
Your previous keyword content won't do much to boost your site's rankings. You will need new content, new pages, and new backlinks to reoptimize your website for the new keywords.
The structure and hierarchy of the site may need to be adjusted.
A Few Tips:
Before you make the change, consider these things to ensure everything goes smoothly:
Consider giving the current page at least 3-6 months to rank before changing your target keyword.
Analyze how much content can be reused. In some cases, changing the wording can suffice, while in others, the whole page needs to be restructured. As a result, it's resource-efficient to determine how much new content you need to create when you change your target keyword.