May I cancel request money transaction before receipt or refund after receipt

[cobra_fat]

I have offered to sell five 2011 American Silver Eagles which were bought in mid Jan. for $42. They each would qualify for First Strike qualification had they been sent to PCGS before Feb. No action has been taken in the last few days and the price of silver is approaching $40. These are now worth at least $46 each (I am selling on Ebay for $48).

Is it possible to revoke this 'request money' transaction? If not, am I allowed to refund it and what would be my penalty for doing that?

[cobra_fat]

Let me explain some possible confusion in my message. They were bought in mid Jan, but not for $42 as my post may be read. I probably spent about $30 each. I am offering to sell them for $42 in the request money.