Nope, sorry bud. But if you want to reset your digimon you can go lose 3 fights and pick a new egg. At that point getting Gabumon is up to you. if I remember correctly the blue egg is the one that typically follows the Gabumon line, but even baby and in-training digimon have branching paths so good luck.
I don't know if killing it to reset the egg has side effects or not, so to be safe if you want a completely fresh start with Gabumon, you can choose not to pass on some of the strength from the original.