You might be able to do this yourself. First you need to take the bottom cover out to look underneath. *Usually a friction clamp. push it up out of the way and tip the top of the cover towards you and then up. You will see where the pedal connects to a wooden lever. Follow the lever and you should see a wooden dowel. The wooden dowel will have a pin in the bottom and at the top. Often times the wood or the pin will stick or hang-up, and then fall out. All you have to do is put the pin back in both the top and bottom. It will be easy once you see it. Of course there are small variants of this system, but it is pretty basic. The other thing you might see is that the wooden lever has cracked. If that is the case call your local piano technician. If you don't know of one, call piano tuners - they are either a piano technician themselves or will be able to refer you to someone who is.
10th June, 2017