remove forgotten activation lock id & password from series 3 apple watch

I ve a series 3 watch purchased from Japan in 2018, i had paired it with my iphone 6s. I ve recently exchanged that phone with android phone. Now i want to pair that watch with my daughter's iphone15. On pairing it is asking for activation lock. on logging to my apple id it is not showing any watch. how do i reset and pair. It is giving me hint of my other mobile no, but i don't remember its id & password