How to create if else statement for execution stored procedure?

How to create if else statement for execution stored procedure?

I have tried this query

IF exists ( select *,count(*) from [nsqm].[dbo].[Table_1]  
            group by col1,col2,col3,col4 having count(*) = 1 )
   exec insert_table_1;
ELSE 
   PRINT 'no duplicate row';

I have message error like this:

Could not find stored procedure 'insert_table_1'.

Im sure stored procedure 'insert_table_1' is exist