Will This Affect the Ranking of a Website?

My website currently ranking for a few keywords.

My Permalink structure is: Website.com/blog/title

If I changed that to this: website.com/title

Will This Affect the Ranking of a Website?

It will nuke your site for 4 to 6 months.

Then, if you did everything right (301 etc) when it returns it might recover somewhat.
 
Even the slightest change in the URL structure will make it a new link in the eyes of Search engines. So better put in some more thoughts before you change them. If you have done any link building for the particular link then i suggest you to make use of 301 redirect.
 
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