The Bureau of Lost Dreams

Being able to go back in time and put right a past mistake has always been an impossible dream, until now. Shackleton Sheckley has unlocked the secret of time travel and his company offers clients a chance to take a trip into the past, but only for an hour. Afterwards, they will return to a new present day that has been created as a result of whatever they changed in the past. Shackleton's latest client is Federica Albright.
She hopes to change something she once did that she's always regretted, but, as she will learn, the result of tinkering with your past is never what you expect.