Hi Rosa,
Normally all that is needed to change from US <-> Rest of World dates scheme
is to use Format|Cells|Dates, But I suspect the dots in you dates are
causing a problem. You may need to extract the three numeric values and make
a 'date' out of them.
Here is one way with your date in A2 (there could well be better ways -
text functions are not my speciality)
dd(in C2) =MID(A2,1,FIND(".",A2)-1)
mm(in D2)
=MID(A2,FIND(".",A2)+1,FIND(".",A2,FIND(".",A2)+1)-FIND(".",A2)-1)
yy(in E2) =RIGHT(A2,2)
date =DATE(E2,D2,C2)
Having got the correct dates you can use Copy followed by Paste Special as
Values to let you delete all the intermediate stuff.
Bernard