Hi Hayden 

Thanks for posting in the community! As an admin it is only possible to view and edit others' work if it is directly shared with you; there are not inherent collaboration permissions that come with the admin role. I recommend reaching out to your colleague and asking them to share the document with you with appropriate editing permissions. Instructions on how to do so as well as more information about sharing work in Lucidchart can be found in this Collaborate and Share article from our help center. Please let me know if you have any other specific questions!