When you remove the personal LinkedIn account through which the business page was connected, the LinkedIn business page will automatically be removed as well.
To know which is the business page under Social Marketing > Settings > Connect Accounts > LinkedIn, it will show the word "Page," and when you click on it, the URL will have the word "company" in it. The personal or individual account will show the word "Account" and its URL does not have the word "company" in it.
Meanwhile, you are able to remove the business page in Social Marketing, and it will not affect the connected personal account.