Update HCM email and username

Summary: There is an upcoming internal change within our organisation where our email address will change. our email address is also our username.

I have been researching on the community and it looks like updating username and email is ok to do but I would like to confirm that it is ok to update user email and username and what is the resulting effect on user accessing data? will user still be able to access prior data e.g. Purchase orders

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Version (include the version you are using, if applicable):23D

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