How do you change what your tag shares later?
By rewriting it, if you still hold it. That is the quiet advantage of a personal tag over a card you handed out, and it changes what is safe to write on one. A tag in your pocket is editable in a way a card in someone else's wallet never is.
A tag you keep is editable
Rewriting takes seconds. A new number, a new page, a different profile, and the object is unchanged.
So for a tag you present rather than distribute, writing details directly is a smaller commitment than the same choice on a business card.
The condition is that it was never locked. Locking a personal tag removes the only advantage it had over a card.
Never lock a tag you keep. There is no benefit and it converts a flexible object into a frozen one.
A tag you gave away is not
The moment a tag leaves your hands it is frozen, whatever it holds.
If it holds a link to a page you control, that is not a problem: change the page and everything you ever gave away follows.
If it holds your details directly, they are wrong from the day anything changes, in the pockets of everyone you met.
Which is why a tag you distribute and a tag you keep are genuinely different design problems, even when they look identical.
Designing for both
Use a link for anything you hand over, always.
Use whatever suits for a tag you keep, including written details where the offline case matters to you.
And keep the two separate, so you do not casually give away a tag that was written for keeping.
That is easier than it sounds: the one you keep can be an object you would not hand over, such as a keyring or a sticker on your own phone.
Making the change stick
Read the tag back after rewriting. A write that reports success and did not persist is a real failure and the only way to catch it is to look.
Check every tag you own rather than the one you were thinking of. People accumulate tags and forget which holds what.
Keep a short note of what is on which, which sounds excessive for three tags and is exactly right after two years.
And update the printed version if there is one, since a tag corrected beside a stale printed line is a confusing object.
Frequently asked questions
Can I rewrite a tag I already gave someone?
No. It is frozen once it leaves your hands, whatever it holds. Only a link to a page you control stays changeable.
Should I lock my personal tag?
No. Locking removes the one advantage a tag you keep has over a card you gave away.
How do I know the change worked?
Read it back. A write can report success and not persist, and looking is the only way to find out.
What if I have several tags?
Check them all and keep a note of what is on which. People accumulate tags and forget.