Question: I want to change INT to INTERNATIONAL and NA to NATIONAL ASSEMBLY in whole excel workbook through an excel Macro or Find and Replace dialogue box. But when I run the macro or change it through Find and Replace dialogue box it also replace NA from CHINA last 2 characters and it became CHINATIONAL ASSEMBLY and INTERIOR to INTERNATIONALERIOR.

Now, I want that Excel should only smartly find the character NA in the workbook which is not included with any other character likewise character INT which is not attach to any other character.

Answer: 
If the values you are looking to replace are by themselves in the cells (no other text), definitely follow [CharlieRB's solution](https://superuser.com/a/474182/143655). If the values are located in the cells, along with additional text, a slightly modified version would work.

Open the Find and Replace window. Click the "Replace" tab.

![Find and Replace](https://i.stack.imgur.com/5cqgK.png)

Enter the "Find what" and the "Replace with" values. Click the "Find All" button.

Review the list at the bottom that details what records were found. Highlight the record you want to update, and click the "Replace" button.
1. Save your file as a CSV file.  If you want to manipulate a subset of your worksheet (e.g., selected columns and/or rows), copy that region into a scratch file (or sheet) and save that as CSV.  If you need to modify multiple sheets, repeat this process for each sheet.
2. Edit the CSV file with some sort of smart text editor (i.e., smarter than Notepad).  `vi` is good for this; use a command such as `%s/\<INT\>/INTERNATIONAL/g`.  Microsoft Word will probably suffice; use the “Find whole words only” option under `More>>` in “Find and Replace”.
3. Read the edited CSV file back into Excel.
4. Copy the modified values into your original workbook, to preserve formatting.