How do I Cancle an offer

[nanotankmates]

hi I was wanting to know how to Cancle an offer? I placed an offer on an old book of stamps then found the picture outside of the booklet is not of the stamps inside its the author vs the sled dogs. Anyway was hopeful to Cancle the offer since I don't want the guy on a stamp I wanted the dogs and can't figure out how to Cancle the offer. I have sent the seller a message but no response either way and just want out of this offer if at all possible. Any ideas