How long of a contract do you have with the broker.My bet is that if you cancel before the end of the contract and the house sells you are on the hook for a commission. The only way would be to cancel, take the house off the market until after the expiration of the original contract, then relist it.
Be aware that Some brokers will play a game and list your house at the price you want even though they know that the price you want is too high. Near the end of the contract term they come to you and tell you the reason no one looked/bought the house is it is to high priced and you need to cut the price. It is the way the game is played sometimes in order to get a listing. If I am a broker and come to our house to get a listing when you tell me you want $250,000 for your $190,000 home I can either tell you the truth and walk out without the listing or take the listing at the higher price knowing I may be able to reason with you later. search your soul to see if you are one of those clients.
On the other side some brokers intentionally price your house too high to get the initial listing. They know that after signing the initial time very few clients will change brokers. After the initial time the broker comes to you and shows you comparables and tells you to lower the price to get a sale. The more time has passed the more desperate some become the easier they are to play the trick on.