Head Ambassador Removal

Tutorial on how to remove a current Head Ambassador. They need to appear in this list for it to work. Note that they can immediately re-apply after being removed.

1. Prepare the Preimage on the Collectives Chain

• Go to PolkadotJS and decode this extrinsic.
• Click on Submission to modify the parameters:
• 
• Replace the addess who with the HA that you want to remove.
• Copy the encoded call data (not the hash!)
  
• This will look different for everyone.

2. Prepare the Preimage on the Relay chain

• Go to the Relay chain with this link.
• Click on Submission again and paste the preimage from above in the call: XcmDoubleEncoded field in the bottom:
  
• Once you are done, again copy the encoded call data (not the hash!)

3. Place the preimage on the Relay Chain

• Go to Developer->Extrinsic
• Create a Preimage::notePreimage(bytes) extrinsic.
• The bytes are pasted from the relay preimage that we created above.
• 
• Click on Submit Transaction. Note that it will reserve a deposit for the preimage; having about 50 DOT on the address is a good idea.
• Go to Governance->Preimages and find your preimage there:
• It should look something like this:
  
• Copy the Hash and Length for later.
• If you want to double-check these values, you can go to Developer->Storage and query Preimage::preimageFor with these details. It should print the Relay Preimage that was pasted in there earlier:
  

4. Create Referendum

• Go to Subsquare track 13: https://polkadot.subsquare.io/referenda/tracks/13
• Click on New Proposal
• Paste in the preimage hash and length from above. This must be correct, otherwise it won't work!
• It should eventually produce this event:
  

5. Offboarding

• Last step is to offboard the HA from the Core pallet after they were removed from the Collective with AmbassadorCore::offboard(who).
• Anyone can call this, but not root. Therefore you have to do this manually after the referendum passed.
• It should produce an event like this.
  

6. Testing

• Clone the moonbeam-tools repo.
• Run a local chopstick fork of the Polkadot Relay and Collectives parachain with: npx @acala-network/chopsticks@latest xcm -r polkadot -p polkadot-collectives. For me locally this only works with @0.12 instead of @latest, maybe a bug in Chopsticks.
• Run the proposal with: npx ts-node src/tools/fast-execute-chopstick-proposal.ts --url ws://localhost:8001 --proposal-index NUMBER Be sure to replaceNUMBER with your referendum index.
• If you get a weird Javascript error, then try npm install first inside the repo.
• After doing this, do the Offboarding step 5.
• Check the state for AmbassadorCore::members and AmbassadorCollective::members that the HA was removed from both.