I want to convert
- Pantone PMS282 C
- Pantone PMS2727 C To TPX or TPG, how to proceed?
You can cross reference Pantone colours with TCX or TPG colours by using the Pantone Connect service. You can sign up for a free account and see/search the colours. However, the cross referencing functionality requires a paid account unfortunately.
If you don't need complete accuracy, it might be possible to add a Pantone colour to your palette in the free version of Pantone Connect, and then add a TCX/TPG colour which is visually close, and compare the two. There's probably not an exact 1:1 colour match anyway, even if you do use the paid cross referencing functionality, so eyeballing it might be sufficient for you.
Another method is if you have access to a Pantone solid colour guide book and TCX colour samples, you could try matching the samples visually.
Note: I have no affiliation with Pantone or the Pantone Connect website.