Silent-Riddick

ok im a newb at all this coding stuff but i was wondering has anyone found a code that allows me to redo the starter pokemon? i found a code so i can go get anothr starter of steven in silph co. the 3rd gen ones but i want the 1st gen ones in OAK's lab i only found 2nd and 3rd gen redos i wanna do the 1st gens so i can get a squirtle this time thanks in advance oh yes this is for pokemon heart gold UK