Merge two .xls files into one .xls file

So I'm trying to merge two .xls files into one .xlsx file. The excel files have all the same common column titles but they have different titles names such as "Change Impacted By CCT-GOT" and "Changes Driven By CCT-GOT" at the top of the report. What I'm trying to do is merge those two reports into one single report with the same column titles. But I cant convert the .xls files into .xlsx extensions. Is there anything I'm doing wrong and by extension if it will merge into one report using my script?

```

$reports =Convertto-Excelxlsx"C:\merged\*"-Force
$mergereport =@()


foreach ($report in(Get-ChildItem"$reports\*.xlsx")){

$report_content = foreach ($row inImport-Excel $report){[PSCustomObject]@{"OSMOR Report"= $report.Name"Change request"= $row."Change request""Change Title"= $row."Change Title""Technology Portfolio Driver"= $row."Technology Portfolio Driver""Planned Start Date"= $row."Planned Start Date""Planned End Date"= $row."Planned End Date""Phase"= $row."Phase""Change Type"= $row."Change Type""Opened By"= $row."Opened By""Task Description"= $row."Task Description""Task Number"= $row."Task Number""Assigned To"= $row."Assigned To""Assignment Group"= $row."Assignment Group"}}
 $mergereport +=@($report_content)}

 $mergereport |Export-Excel"C:\OSMORmergedreport.xlsx"

```