When inner conversation disappears, the "doer" disappears. How does the "knower" disappear, during vipassana meditation?
Knower dissapears when "knowing" disappears.
How to achieve this?
Complicated answer is: with stopping craving.
Simple answer is: with calming of the mind and letting go completely.
The distinction between idea and experience falls away. Samsara and Nibbana are actually seen / known to be one thing. It just happens. Concepts and questions no longer hold one's attention for long.
According to the Dhamma that Master Mahā Kaccāyana teaches, it's not easy living at home to practice the holy life totally perfect, totally pure, like a polished shell ...read
See also "The fruits of the homeless life: DN 2"
The "knower" and the "known" disappearing is the last in line: ceto-vimutti & panna-vimutti.
"This, too, great king, is a fruit of the contemplative life, visible here and now, more excellent than the previous ones and more sublime. And as for another visible fruit of the contemplative life, higher and more sublime than this, there is none."
To understand the message possible better: householder stands here for "knower" and the six doors (senses and consciousnesses) for the "known".
It's not possible to gain liberation, as long one is not disenchanted, has no desire for a home.
Your external home (six sense) isn't your real home.
It's your supposed home, your home in the world.
As for your real home, that's peace.
The Buddha has us build our own home
by letting go till we reach peace.
[Note: this is a gift of Dhamma and not meant for commercial purpose or other low wordily gains.]