Here is a screenshot of how this tool works. If you think this can be useful to you, you can follow the instructions in the description below:
How it works in MS Excel
In Excel you will use a custom formula to convert the unicode text to legacy text and vice versa.
How it works in MS Word
In Word you will use a shortcut key / ribbon shortcut to convert the unicode text to legacy text and vice versa.
Installation Instruction for Excel
Step 1: Download the Excel Addin File from this link. 
Step 2: Install the Addin File
(i) Open your “Microsoft Excel”
(ii) Go to “Files”
(ii) Go to “Options”
(iv) Go to “Add-ins” tab in the new window
(v) At the bottom at “Manage” Section choose “Excel Add-ins” and click “Go”
(vi) Click “Browse” and browse and select the file downloaded from Step 1
(vii) Click “OK” and return to Excel Spreadsheet
Step 3: You can start to use the tool.
Step 4: The Functions
UnicodeToPreeti(UnicodeText)
PreetiToUnicode(PreetiText)
Note:
This function only has a single argument for the input text and nothing else. It’s fairly simple.
Follow this post for more updates. You can later download more latest version of this tool here in this same post.
Installation Instruction for Word
Step 1: Download the Word Addin File from this link.
Step 2: Install the Addin File
(i) Open your “Microsoft Word”
(ii) Go to “Files”
(ii) Go to “Options”
(iv) Go to “Add-ins” tab in the new window
(v) At the bottom at “Manage” Section choose “Word Add-ins” and click “Go”
(vi) Click “Browse” and browse and select the file downloaded from Step 1
(vii) Click “OK” and return to Word Document
Step 3: Assign a shortcut key or ribbon shortcut
At this stage you already have the tool. You just need to either assign a keyboard shortcut to the macro or enable a button in the toolbar area.
(A) You can either assign a shortcut key:
(i) Go to “Files”
(ii) Go to “Options”
(iii) Go to “Customize Ribbon” tab in the new window
(iv) At the bottom at “Keyboard shortcuts” section choose “Customize”
(v) On “Categories” group select “Macros” and on “Macros” group select the required macro
(vi) Press shortcut key and click “Assign”
(vii) Click “OK” and return to Word Document
(B) Or, you can setup a ribbon shortcut:
(i) In the top of the ribbon area click “Customize Quick Access Toolbar” and go to “More Commands”
(ii) On “Choose Commands from” group select “Macros” and select the required macro
(iii) “Add” the macro to the other group
(iv) Click “OK” and return to Word Document
Step 4: You can start to use the tool
You can start to use the tool.
Follow this post for more updates. You can later download more latest version of the this tool here in this same post.