CREATE PROCEDURE dbo.GetTableData(
    @TblName   VARCHAR(50),
    @Condition VARCHAR(MAX) = NULL,
) AS
BEGIN
    IF(EXISTS(SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = @TblName))
        BEGIN
            DECLARE @SQL NVARCHAR(MAX) = N'
            SELECT * FROM @TblName WHERE 1=1'
            + CASE WHERE @Condition IS NOT NULL THEN
            ' AND ' + @Condition ELSE N'' END

            DECLARE @params NVARCHAR(MAX) = N'
                @TblName   VARCHAR(50),
                @Condition VARCHAR(MAX)';

            PRINT @SQL

            EXEC sys.sp_executesql @SQL, @params,
                @TblName,
                @Condition
        END
    ELSE
        RETURN 1
END

EXEC GetTableData 'parts'

EXEC GetTableData 'parts', 'supplier LIKE ''A2A Systems'''

EXEC GetTableData @TblName='parts', @Condition='supplier LIKE ''A2A Systems'''