Sometimes the name you initially assign to a variable turns out not to be the 'best' choice.
Let's say you called a variable [Date] and then decided it should be [Date of Contract] so that it would be more meaningful to the end user.
Or, perhaps even more widespread, you assigned a variable [Name of Client] and days or weeks later decided that [ClientName] fit your naming scheme better (to make it consistent with [ClientAddress], [ClientCity, ST ZIP]).
Or, perhaps you decided that you want to break up a variable like [ClientName] into its components, such as [ClientFN], [ClientMI] and [ClientLN].
Not to worry. You can easily change any variable to a value more to your liking at any time.
If you are just getting started, and have only created a few variables, manually changing them is probably the easiest course. But if you have spent a lot of time creating variables before you decided a different name(s) was in order, see Search & Replace for how to make those changes in a more global fashion.