Question

replace(replace(Names,'Lara',''),'M','') 

is working, but

declare @midname varchar
set @midname = 'Lara'
replace(replace(Names,@midname,''),'M','')

is not working

Answer 1

You should put your code in a code box. It is hard to be sure what you have but this should work.

DECLARE @midname varchar(200); 
SET @midname = 'Lara'; 
SELECT Replace(Replace(Names,@midname,''),'M',''); 

Names looks like it should be a variable, not sure about how you are using it.