"Sum of" in column heading in pivot table

[Guest]

When I move a column titled January into a column area of a pivottable the
title says "sum of January". I cannot change it to "January" without an
error "pivottable field name already exists". Yet if apply an autoformat to
it the lable says "January". How can I format manually so the label does not
includ "sum of"

 

[Myrna Larson]

Include a space at the end, or a period, i.e. January.