A Keepsake That Holds More Than a Memory

Yes. As long as the NFC tag has not been permanently locked, you can replace the programmed link with another one. 

the NC tag stores only the link. Your photos, videos, recordings, or other content remain with the online service where you choose to host them. 

NFC capabilities vary by phone model and settings. Most newer smartphones support NFC, but compatibility cannot be guaranteed for every device. 

If your NFC tag links to online content such as a video, photo album, or webpage, the phone will need internet access to open that account. 

Privacy depends on the service you use to host your content. If you create a public or "anyone with the link" page, anyone who receives that link may be able to view it.