Changing multiple text values to a single text value

I would look at creating a Group in DAX. You could create a group for each of your 4 values and then include an "Other" group. I think this would be the quickest and most efficient way of doing what you are looking to do. In your fields area, click the ellipses (...) and choose "New group". 

Hi Fahid

You can add a custom column in the query editor with the following code:

= if List.Contains({Val1,Val2, Val3, Val4},[YourCurrentColumn]) 
     then [YourCurrentColumn] 
     else "Other"

where Val1-4 are the values you want to keep

Then, if necessary, you can remove the original column and rename the new one

Fahid

It doesn't turn all rows to others. Like I said, Val1,...Val4 are just examples and you have to substitute them for the values you want to keep (you haven't said what those values are). You cannot use "Val1"... "Val4"