I would like another phrase instead of "for that reason."
closed as not a real question by Noah, David Schwartz, F'x, Matt E. Эллен♦, RegDwigнt♦ Nov 5 '12 at 10:56
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If you are proposing to use "for this purpose" in place of "for that reason", then I think you will have difficulty.
My first interpretation of "for this purpose" refers to a function or a process to be carried out. I would use it in sentences such as
When the group realised that the water needed to be filtered to remove leaves and bugs, Lisa used her new scarf for this purpose.
Although candidates are permitted to bring reference material to the examination, the prescribed textbook must not be used for this purpose.
In neither case, could "that reason" be used instead.