How can i deflate my ball. The ball i bought was from Walmart's ball cage.?

It looks like this : http://www.google.com/imgres?imgurl=http://ecx.images-amazon.com/images/I/41qDMIEqDML._SL500_AA300_.jpg&imgrefurl=http://www.amazon.com/BOUNCE-HEDSTROM-54-9421-RUBBER-PLAYGROUND/dp/B000KLW476&usg=__kCgw25k9bfo6M5vZQ0btDsR33dI=&h=300&w=300&sz=17&hl=en&start=0&zoom=1&tbnid=TfZpSRP8IdYXlM:&tbnh=162&tbnw=208&ei=hragTZj1KInC0QGNhPChBQ&prev=/images%3Fq%3Dhedstrom%2Bball%26um%3D1%26hl%3Den%26sa%3DN%26biw%3D1366%26bih%3D667%26tbm%3Disch0%2C21&um=1&itbs=1&iact=hc&vpx=160&vpy=243&dur=1271&hovh=225&hovw=225&tx=177&ty=142&oei=J7agTaquPKSU0QHm5pSABQ&page=1&ndsp=20&ved=1t:429,r:7,s:0&biw=1366&bih=667