unit FormMain;
...
procedure TfmMain.ShowRepairObject(AIdent: Variant);
begin
  TfmRepairObject.OpenForm(Application, AIdent);
end;

unit RepairObject;

uses ..., System.Generics.Collections;

type
  TfmRepairObject = class(TForm)
  ...
  private
  ...
    FList: TList<TfmRepairObject>;
  public
    Ident: Variant;
    class procedure OpenForm(AOwner: TComponent; AIdent: Variant);

    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
  end;

implementation

uses ...

...

constructor TfmRepairObject.Create(AOwner: TComponent);
begin
  inherited;

  FList.Add(Self);
end;

destructor TfmRepairObject.Destroy; override;
begin
  FList.Remove(Self);

  inherited;
end;


class procedure TfmRepairObject.OpenForm(AOwner: TComponent; AIdent: Variant);
var
  fm: TfmRepairObject;
  Found: Boolean;
begin
  Found := False;
  for fm in FList do
    if fm.Ident = AIdent then
    begin
      Found := True;
      fm.Show;
      Break;
    end;

  if not Found then
    with TfmRepairObject.Create(AOwner) do
    begin
      Ident := AIdent;
      Show;
    end;
end;

end.