how to re-frame an existing house corner

[George P.]

i have a corner that has rotten wood due to long term leak (years). the bottom of 5-6 two by fours are rotten and the bottom plate is rotten.

the outside is brick, so i can't get to it from the outside. how do i replace the bottom plate and the vertical studs with new wood before i sheetrock?

i can post a picture of the studs without drywall if needed. the corner is in a closet.