Re-write or Re-direction

I want the current http://ABC.com/4/5/WT site to point to a maintenance page on ABC01.com/Mt while they do the change

if using HTTP::redirect, url at browser will be changed (to http://ABC01.com/Mt).

in case you do not want to change url at browser (http://ABC.com/4/5/WT), you may have to set ABC01.com as a pool member and change uri using HTTP::uri.

then permanently to point to http://XYX.BBB.com

sorry but what does it mean?