Question

is it possible to reallot by sending a packet to reallot to the server?

probably yes, but you would still need a db:)

Yes it is but you need to be near the NPC and you need to have a DragonBall in your inventory.

Yeah I tried that already and it's exactly as choco and mind said, but I was wondering, is it encrypted in the packet to take the DB from you or is it a command from the server when you send the packet? Because if it was in the packet you can just change it to something like Vanilla.

All you are doing in the packets is to tell the NPC to reallot pots, depending on the implementation the NPC window will show up or not. There is no other known way to do it.