TOTALLY WRONG !!!
Let us say you have your search campaign's keywords as "catering, caterer" and your ad copy also pertaining to "catering, caterer" and your landing page (website) also pertaining to "catering, caterer".
Then you leave the search campaign as it is (pertaining to "catering, caterer"), BUT HOWEVER you change the landing page (website) to something to do with furniture, etc, (EVEN IF WITHIN GAds policies) then BOOM, your ad will (very soon) get disapproved and / or account suspended. Because GAds review bots are continously "scanning" landing pages (websites) that have ads in GAds. And if the search campaign AND landing page (website) are not very well in sync with eachother, then ad will soon get disapproved and / or account suspended, even though both are individually within GAds policies.
So, the following is WRONG
Truth is even if you change your landing page (website) to something within GAds polices, BUT your GAds campaign due to your change in landing page (website), no longer is within the exact niche of your changed landing page (website), then it WILL be a problem, ad will very soon get disapproved and / or account suspended.