need help updating new location from combo box into a subform query in access using vba.

Your picture gives us a rough idea of what you want to do, so here's a rough idea of how to do it:
Assuming the record you want to update is selected in the subform as seen in the picture and assuming that the name of the Location field textbox is "Location", and assuming that there is a location value is in the combobox when you click the "Update Location" button:

Me.subFormControlNameHere.Form.Location = Me.ComboboxControlNameHere

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This is a simple way to do it.  There's are several others, but no need to get any more involved given what we know so far.

Also, please don't use PowerPoint to provide images. A simple screen capture works much better, and many Experts simply won't open files like this (or don't have or use PowerPoint).

I agree with Scott.  
Windows 10 comes with a "Snipping Tool" (found under "Windows Accessories") which is what I use to snag pieces of screens.  
You can save them as files for insertion into EE posts, etc., or paste them into Word, etc.
Also, I got the screenshot of the Snipping Tool below by holding down the Shift key on my keyboard and pressing the "Print Screen" key on my keyboard which puts it on the clipboard, then pasting the screenshot on the clipboard into Word, where I right-clicked on it to "Save As" an image file.  You can also edit the screenshots in Paint or some other image edit app.
If you Google "Snagit", you'll find out it is not free, but you'll also find a few links to quite a few similar apps that are.
TIP:  If the image in EE posts are unreadable, like the one below, click on it to expand it into its own browser window so you can read it.

I use simply Print Screen and IrfanView....Select the Screen portion that you need and CTRL+Y to crop accordingly..CTRL + S to Save

getting the error 'record set not updateable'

lets change gears here for a second.  maybe I can just do a  docmd.runsql UPDATE Returns SET Location = 'LW0119B' WHERE [ID] = '202'
but I do not understand the format exactly.  Please advise

my location table is just linked.  I can't add a primary key

how do I know what 'N' is?

let's put this another way
I have a table called 'Returns' it has a few fields on of which is called 'Location' and It has a primary key on a field called 'ID' which is also  auto numbered
on ID record 202 I want the change the location field value to 'test'.  would the below statement work. if not how do I format it to work (If possible)


docmd.runsql UPDATE Returns SET Location = 'test' WHERE [ID] = '202'

"this worked" means you got what you needed - problem solved, right?

yes thanks for the help