If you have the reservation number, just call HHonors and ask them to add your Hhonors # to the reservation. I have to do this sometimes for business travel when another colleague makes our reservations. If you don’t have the number, they can probably find it with your last name and stay dates.

i have also been able to do this myself online when using the lookup reservation. It requires the last 4 I think of the billing credit card. When I don’t know that card number, I just call and they do it for me.

Then the stay shows up in the app.