Every life insurance policy comes with a free look period. That means a window, starting when the policy is delivered to you, during which you can cancel and get every dollar of premium back. Not a surrender value. Not a prorated refund. The full premium.
How long depends on your state and on the situation. Ten days is the common minimum on a policy you're buying new. When the policy replaces one you already own, most states extend the window, often to 30 days, because replacement is where people get hurt. Some states give a longer window to buyers over a certain age. The exact number is printed on or near the first page of the contract, usually in a box, and it's the first thing to look at when the package shows up.
The clock starts at delivery, not at application and not at approval. If the policy came in the mail, delivery is generally when you received it. If an agent handed it to you and had you sign a delivery receipt, that receipt sets the date. Underwriting can run six weeks, so the gap between "I applied" and "my clock started" can be long, and people who assume the window already closed sometimes still have it open.
What to do with the window is read the contract against what you were shown. The illustration is a projection. The contract is the agreement. Four things should match, and where they don't, you have a question to get answered before the window runs out.
The death benefit and the death benefit option. Level or increasing, and the face amount as it was actually issued.
The rate class. If you applied expecting preferred and the policy came back standard or table-rated, the premium you're paying bought less coverage than the illustration showed. That happens, it's legitimate, and it also means the projection you signed off on isn't the projection you now own. Ask for the illustration to be re-run at the class you actually got.
The riders. Every rider you asked for should be listed and every rider you didn't ask for should not be. A waiver of premium rider or a chronic illness rider that got dropped during underwriting changes what the policy does for you.
The premium and the mode. Mode means how often you pay, and paying more often costs more, which why paying monthly costs more than paying once a year gets into.
Canceling inside the window is a written request, and the carrier will want the policy back. Send it certified, or through the agent with delivery confirmation, and date the request inside the window even if the carrier takes weeks to process it. The date on your letter is the date that counts.
Make sure you don't cancel an existing policy until the new one has cleared its free look and you've decided to keep it. People do it in the other order, find something in the new contract they don't like, and discover the old policy is already gone and their health has changed since they bought it. When a replacement is involved at all, both contracts stay in force until you've read the new one line by line.
Set a calendar reminder the day the package arrives, dated two days before the window closes. Then read the contract in the first week rather than the last, so there's time to get a straight answer out of the carrier while the window is still open.