How to change a gas furnace pilot to a self-electric detonators. ?

Honeywell has a kit I’ve used many times, it involves changing the gas valve, adding a spark electrode to the existing pilot assembly and a control module.
Kit would sell for $250 – $300.00
Labor for a professional might be $65 – $100.00
Recommend a professional, they will warranty what they do and can provide you with warranty on the parts.
Your not going to save enough in fuel to recover the cost of the parts, maybe you should look at replacing.