[rm48ic]

To get cables under the floor, I need to lift the existing tongue and groove floor. It seems to me that there is no way to get it up without damage or any way to insert a new piece(to replace the damaged piece) afterwards as the tongue in the new piece can't be inserted into the groove of the adjoining board

Are the any special tools or techniques needed?

[louishm]

theres a couple of ways of doing it.
the easiest is to use a circular saw, run the saw down both sides of the t&g making sure to set the the depth of the cut so it just cuts the t&g, the board will then just prise up...
the harder way is to use a bolster chisel, insert the chisel into the the groove and hammer the t&g, obviously this is long winded especially if the board is a good few feet long

[Johnny Thunder]

You could also cut the tongue with a stanley knife. The boards
will go down neater afterwards.