This example extends the selection backward until a capital "I" is found.
Selection.MoveStartUntil Cset:="I", Count:=wdBackward
If there's a dollar sign character ($) in the first paragraph in the selection, this example moves myRange
just before the dollar sign.
Set myRange = Selection.Paragraphs(1).Range
leng = myRange.End - myRange.Start
myRange.Collapse Direction:=wdCollapseStart
myRange.MoveStartUntil Cset:="$", Count:=leng