Table.ReplaceValue(#"Step Before Name",

each [YOUR COLUMN NAME],

each if [YOUR COLUMN NAME] ="NORTH" then "N"

else if [YOUR COLUMN NAME] ="SOUTH" then "S"

else if [YOUR COLUMN NAME] ="WEST" then "W"

else if [YOUR COLUMN NAME] ="EAST" then "E"

else [YOUR COLUMN NAME],

Replacer.ReplaceText, {"YOUR COLUMN NAME"})

THE OTHER WAY

Table.ReplaceValue(#"Step Before Name",

each [YOUR COLUMN NAME],

each if [YOUR COLUMN NAME] ="N" then "NORTH"

else if [YOUR COLUMN NAME] ="S" then "SOUTH"

else if [YOUR COLUMN NAME] ="W" then "WEST"

else if [YOUR COLUMN NAME] ="E" then "EAST"

else [YOUR COLUMN NAME],

Replacer.ReplaceText, {"YOUR COLUMN NAME"})