Open XML: Convert open XML string to byte[]

Question

Hi All,

I am trying to search and replace a string in word document which is stored as byte[] in database. I am referring to below sample:

https://learn.microsoft.com/en-us/previous-versions/office/developer/officetalk2010/ee945362(v=office.11)?redirectedfrom=MSDN

I can see that text is getting updated in open XML string but same is not getting updated in file.

And I need to convert the updated Open XML string to byte[] to store it back in database. Please help.