Changing selections in a drop-down menu/list

Hi there,

I recently inherited an old spreadsheet at work that includes a drop down menu with six options (our US offices). Selections tagged from this drop-down list automatically update fields in other linked spreadsheets.

I need to add an office, but can't figure out how to modify the list of options in the drop-down menu. Can anyone help?

Thank you!!

Got it - thank you!