On spyro's aventure (on the game system can't.
But,if you are talking about spyro's universe (online computer game)
here's the steps
.
1.)go to your skyland
2.)drag your arrow down to the hammer on the bottom right corner and click it
3.)click the two arrows going the opposite direction of each other
This will work but, you can only upgrade a sertain ammount of times depending how many skylanders you have registerd.(if you have all the skylanders registerd i THINK
you can go upgrade eight times.)
My skylanders
Magic:Spyro,Wrecking Ball,Voodood,Double Trouble
Earth:Bash,Terrifin,Dino Rang,Pismb break
Water:Zap,Slam Bam,Gill Grunt,(can't find Wham Shell!)
Fire:Flame slinger,Sunburn,Eruptor(Need to buy Ignitor from My Mom.)
Teck:Trigger Happy,Drobot,Drill Sergent,Boomer
Undead:Cynder,Hex,Ghoust Roaster,Chop,Chop
Air:Whirlwind,Sonic Boom,Warnado(Need to buy Lightning Rod from My Mom.)
Life:Camo,Stump Smash,Stealth Elf(Need to buy Zook from My Mom.)
CAMO IS MY ALL TIME FAVORITE!
You Must complete all Heroic Challenges And Upgrades