Changed His MInd About Selling

I haven't seen your listing contract, but if it's like most, you certainly have the right to cancel the agency you gave about the sale of your house, and you probably promised to pay a commission only if a buyer was produced.  If your agent gives you an argument, talk with the managing broker in that office, because your contract was made with the company, not the individual salesperson.  You may be asked to reimburse them for out-of-pocket expenses like advertising, but in many cases you won't be.