Conventional mortgage insurance must be cancelled at your request at 80%
“A borrower may request cancellation of private mortgage insurance when the principal balance of the loan reaches 80 percent of the original value of the property.”
You do not need to refinance to remove it. Once the balance hits 80% of the original value — through payments, extra principal, or an approved new appraisal under lender rules — you can ask for cancellation in writing.