To find a relative date 12 weeks in the future from 24th December, you can manually calculate it by adding 12 weeks to the given date.

First, convert 24th December into days, which is the 359th day of the year. Then, add 12 weeks (84 days) to 24th December.

This calculation would bring you to 16th March of the following year. Thus, 12 weeks in the future from 24th December is 16th March.

Remember that while each week has 7 days, in this case, we are considering 12 weeks as 84 days for simplicity in the manual calculation process.