Note of caution: Never melt your original game package - If it goes, so does your access to the game.
If like me you have CCU'd your original game package ship and have value locked into a ship you don't want, you can melt the game package and buy it back from your buybacks list either with fresh money or by using a bit of the store credit you have unlocked, but you only get one Store Credit Buyback token every 3 months to do this with so if you want to use credit make sure you have a token.
EXAMPLE:
You have an Aurora MR game package. You CCU'd it to a Hornet Ghost, but then the 100i concept sale happened and you learn about LTI and want it. The Aurora costs $54 and the Hornet Ghost $150 - you have a total of $150 locked in this ship, locked to your game package.
Melting the game package gives you $150 Store Credit but takes away your access to the game so you need it back ASAP. You can now either pay $54 in new money to buy your game package out of buyback, OR you can use $54 of your store credit and say bye bye to your credit-buyback-token until it is refreshed at the end of the quarter.
You now have your game package back and either $96 store credit and no buyback token, or $150 store credit, your token and a spend on new money of $54. The store-credit-buyback token is not worth anything as it refreshes, so your choice.
So, how to put LTI on your Hornet Ghost?
The 100i came with LTI during the concept sale and cost $45. The Hornet Ghost costs $150.
Buying the LTI 100i costs $45 in real money and cannot be bought with store credit and retain the LTI, so this is a new-money cost. The next concept ship sale may be more expensive, it may be even cheaper, that is an unknown but the value of the concept ship will go into the value of the ship you actually want so you can't really loose out there... your intention is to buy LTI and sort of "pay a deposit" on the ship you actually want.
Now you have an LTI 100i for $45. You can now buy a CCU (cross chassis upgrade) from the 100i to the Hornet Ghost - the CCU costs the difference between the two ships, so in this case $105. This can either be bought with fresh cash, or with the Store Credit from the original melting in this example ($96 needing $9 new money too if credit was used for the buyback, or from your store credit leaving you with $45 store credit if you bought your game package back with new money).
WARNING: be aware, If the LTI ship is more expensive than the ship you are aiming for, you can't CCU to it.
Once the CCU is bought, go in to "My Hanger" in your account click on the CCU and it will instruct you from there how to apply it to your 100i.
Job done, you now have a non-LTI Aurora MR which is tied to your game package and an LTI Hornet Ghost which you can how happily throw at things without a care in the world if it gets scratched.