How to combine two rows in a data table into a third new row, such that the values in the row are added together in the new row?

"","STATUS","N"
"1","Resolved",650
"2","Assigned",135
"3","Closed",530
"4","In Progress",56
"5","Pending",75
"6","Cancelled",20

I need to change the "dt_count" data table to a new data table that looks like this:

"","STATUS","N"
"1","Resolved/Closed",1180
"2","Assigned",135
"3","In Progress",56
"4","Pending",75
"5","Cancelled",20

Or, to state the question:

I need to combine the "Resolved" Row with the "Closed" Row, into a Third new row titled "Resolved/Closed", whereby the "N" ticket count in each of the "Resolved" row and the "Closed" row are added together in the third new?"Resolved/Closed" - also, would need the old?"Resolved" Row with the "Closed" Rows to go away.

To complicate the issue, the rows in the "dt_count" data table when they are output, are not always in the same order.

I have the data.table library is installed.

I'm thinking there is a very easy way to do this... but I am not finding it. I've spent several hours searching thru among other things? - several data table cheatsheets, and I've also read thru this:
https://cran.r-project.org/web/packages/data.table/vignettes/datatable-intro.html

Just can't sort it out. Just started using R a few weeks ago.

Any help would be so very much appreciated!

Thanks.

Gregg
AZ, USA