Change mmm to mmmm ie Mar to March

Hi,


I am trying to change the value of a cell which contains the name of the month in Mmm format into Mmmm format.

I would like to to this without using the vlookup function.

Any help would be appreciated.

ie: cell A1: Nov
cell B1: would show November
if the value in A1 is Dec, B1 therefore will be December
Thx