Family Historian User Group

I’m not sure how to explain this but, here goes.
I have person in a census with a particular name (A).
But in another census they are called (B).
In the property box census facts can be added and on the main tab different names can be assigned to the same person.
But how can these alternative names be assigned to anything. ie. a census fact?

Firstly, it is quite common for the details about a person to vary from Census to Census.
Not just their Name but also their Age and Place of Birth are often inconsistent.
As a genealogist you have to judge what is fact and what is fiction.

If the change from name A to B is a formal change such as Deed Poll, Adoption, Celebrity, etc, then see the advice in Knowledge Base > How to Handle People With Multiple Names.

If it is just a nickname, then that can be added to the Names & Titles dialogue, as you say.
You cannot assign an Alternate Name to a Fact or to a Date, but you could add a Note to the Fact or its Citation.
However, the Name can have a Citation that links to the Census Source record from which that Name is gleaned, in the same way the Census Event Citation links to the same Census Source record. That shared Source record gives the coupling between Name and Census Event, in the same way that it couples the Occupation facts, Birth facts, and other household Individuals gleaned from that one Census Source record.
BTW:
The Census Source record Text From Source transcript (and Media image) should show the Name as recorded in that Census, i.e. literally as it appears in the document, and may need manual editing.

To add the Citation to the correct Name field, open the Names & Titles dialogue and select the required Name field.
In the yellow Sources For pane, either Primary Name, or Alternate Name[2], or Name[3], etc, will appear.
Use the Add Citation button to cite the associated existing Census Source record.

Thank you for that Mike.
Although what I wanted is what you say cannot be done, which is assign an Alternate Name to a Fact.
The person in question has different surnames in two different census and as yet cannot determine which is her birth name.
Many thanks though.

That is somewhat unusual ~ are you certain they are the same person?
Is the later name perhaps her married surname?
If you gather other Census records and BMD records it may become clearer

It is more probable that the earlier Census gives her birth name so enter that as the Primary Name.
Enter the other name as the Alternate Name for now. Later on use the Make Primary button to swap them if necessary.
Add Notes where appropriate to identify the dilemma.

You could add her to a Named List for further research, or create a To Do fact, as explained in Knowledge Base > Create Work In Progress or Research To Do Lists. Then you can easily identify those special cases needing further attention.