Question: Is there a formula I can use that will change all cells with one character to something else? 

For example, I have cells with single letters and no matter what the letter is I want that cell to contain the word Member.

**More Info:** I get spreadsheets that contain, up to 40,000 rows. Column B will have names in the cells. Every once in a while a column will just have an initial instead of a full name. I'm looking for a way to change every single cell containing only one single character to the word "Member." The cells that need to change could be any letter but no matter what that letter is, if it's just a single letter in a cell, it needs to change to the word "Member."

Answer: 
Your question is hard to understand. 
I’m guessing that you mean that you have a collection of cells (say, column A)
that contain text values like “” *(blank)*, `A`, `AA`, `AAA`, etc.,
and you want to display “” *(blank)*, `Member`, `AA`, `AAA`, etc. 
Try setting `B1` to

```
=IF(LEN(A1)=1, "Member", A1)

```

and then fill the appropriate part of column B with that formula (e.g., by dragging).
Not sure if you are saying you want the cell that has a single letter ('a' for example) to change to the word Member or not, but here is what I think you are trying to do

```
  A B
1 a =IF(A1="a","Member","")
2 a =IF(A2="a","Member","")
3 b ..
4 c ..

```

the resulting excel spreadsheet would look like this for each cell going down vertically that contains the lowercase letter 'a'

```
  A B
1 a Member
2 a Member
3 b 
4 c 

```