It would definitely cause you problems! In fact people spent so much time trying to do exactly what you suggested that we eventually considered it an exploit and stopped offering technical support for people who corrupted their game in this matter.
If you wanted to do it yourself, you would have to make a new save file. (Uranium Support this feature, so it won't overwrite your existing data.
Step 1: On Save 1, offer your Cometeor in the GTS at your nearest pokemon center. Ask for something very specific that Save 2 has. (Ex. Instead of requesting a Birbie, request a Lvl 6 Female Birbie. This prevents sniping.)
Step 2. Load Save 2 and head over to your nearest Pokemon Center and head into the GTS. Select the Cometeor that Save 1 offered.
Cometeor will now evolve.
Step 3. On Save 2, Send Cometeor back to Save 1 using the same method. (Asking for a very specific pokemon in exchange for your now evolved Cometeor.)
Step 4. Load up Save 1 and complete the trade. You should now have your freshly evolved Poke
If you wanted to do it yourself, you would have to make a new save file. (Uranium Support this feature, so it won't overwrite your existing data.
Step 1: On Save 1, offer your Cometeor in the GTS at your nearest pokemon center. Ask for something very specific that Save 2 has. (Ex. Instead of requesting a Birbie, request a Lvl 6 Female Birbie. This prevents sniping.)
Step 2. Load Save 2 and head over to your nearest Pokemon Center and head into the GTS. Select the Cometeor that Save 1 offered.
Cometeor will now evolve.
Step 3. On Save 2, Send Cometeor back to Save 1 using the same method. (Asking for a very specific pokemon in exchange for your now evolved Cometeor.)
Step 4. Load up Save 1 and complete the trade. You should now have your freshly evolved Poke
Backup your saves, don't lose progress!
C:\users\<Username>\Saved Games\Pokemon_Uranium
Save Backups:
C:\users\<Username>\Saved Games\Pokemon_Uranium\Backups
C:\users\<Username>\Saved Games\Pokemon_Uranium
Save Backups:
C:\users\<Username>\Saved Games\Pokemon_Uranium\Backups
OID: 000003 OT: Cody
