I am about to purchase fontself for creating icons & symbles for catalogues. There is an exsisting face that was created years ago which is in use. The reason for purchase is that some of the icons need to be changed. Each icon is set to a letter of the alphabet i.e. x=flowerpot k=sun v=butterfly.
The question is can I re-create the face and allocate the same letters to each symble. Then when I subsitute the new face the ‘new’ icons will directly replace the old ones.
New icons to replace old
Hi, it’s not possible to edit fonts that were made in another tool than Fontself Maker. Editing OTF font files usually lead to technical glitches when not done appropriately, and in any case most of the font licenses don’t allow to modify them.
So it’s for both technical and legal reasons. 
Hi Fothergills, I understand what you wish to do and the simple answer is - YES it will work.
What you plan to do, is to re-purpose say 90% of a font I figure you purchased and add in symbols/icons to improve your own workflow. I believe you have zero plan in selling or freely distributing the altered font. And if the case - I see no wrong in doing what you plan. Now you did mention this is for catalogue work (commercial) so do not provide this font to anyone. BUT – if the intent is to print these catalogues – distill print ready PDFs to be sent out - not the raw file and collected font. I am not a lawyer or fully understand the legality of fonts - yet if you own the font (paid for it) and follow what instructions I mention here - you should be okay. And I advise you to research the legality of fonts to better understand things.
Moving forward:
You would first, type every single letter you need from the (the old font) out in illustrator.
Next, convert the letters to outlines. Then, port these outlines into FontSelf and add the icons you wish to the set. Note: your icons, need to be outlines also; set them to the keystroke you desire.
When completed, have Fontself package your new font with an entirely NEW NAME not the same. Example if your old font is Gotham, you might call the new one, Golden or MyCatalogueFont.
There are perimeters, creator labels, date, copyright and other data fields when you save the new font. The meta-data can be set for your font - which would typically be done to protect your rights to any font you make. Again, I do not see you selling this font. And even though you call it by another name - it is best to produce a PDF when you wish to print with this font you altered. Again, remember you most likely own the old font - and this is done to improve your own workflow.
Lastly, you want to load into your system, the new font. It should have a unique ID created from Fontself so it will not get confused with the old font. Next open your layout file. Using the font manager within the application, like Adobe Indesign, simply replace the old font with the new font and you should be done.
Again - it is wise to look into the legalities of fonts, the distribution, ownership, copyrights on fonts, etc… for a better understanding of everything - so you are not doing anything wrong.
My apologizes,
You have an older font that consists mostly of icons.
Some of those icons require changing - revisions.
Yes, my suggestion still is correct - however you must type from “A to Z” and “a to z” lower case and “0 to 9” - then all the other special characters before outlining them.
Keep them organized to the way FontSelf likes to import vectors.
Next fix and/or replace the icons you need.
Then select the A to Z and import as Fontselfs re-mapping and re-connects vectors icons to keystrokes. The special characters - remapped might require doing manual.
Just fallow as best as you can, what I had previously mentioned and on save,
FontSelf will create a unique ID - so no worry about getting confused to the old font - still best to provide a new name.
It really does not matter if the old font was paired with a Bitmap and Vector, or a OpenTypeFormat OTF or a TrueType font – in illustrator - the font needs to be converted to a vector - an outlined – before you bring it into Fontself.
Nevertheless, you can achieve with FontSelf exactly what you planned to do.