Coats of Arms are NOT anyone’s, other than the person to whom they were awarded, family or not, you cannot use them as your own! Stephen (who would appear to be from Scotland) has correctly pointed out that there are MANY individuals who will tell you and sell you ANYTHING. You cannot imagine how many North Americans in particular have been given the first C of A that comes out of a computer generated file and paid a small fortune for it, just because the name Smith, or Jones, or Brown or Black are above the shield!
To try and give you an example of how wrong this is, imagine for a moment that your father was awarded the Medal of Honor, the Silver Star or a Purple Heart. Do you honestly think that when he dies, you have the right to wear or represent him by wearing, or claiming “ownership” of them? Absolutely not! They are simply reminders of a courageous individual to whom you are related, nothing more. Even worse, can you imagine 100 years from now, someone telling your brothers, mothers, sisters, uncle, that they can now display your father’s medals as their own…………. Hell no!
Having said all that, if you can prove direct male descent (first son, first son etc), which gentle reader is NOT an easy feat, you can apply to the Lord Lyon for a revision, whereby you can add perhaps a gold (Or) band or a chevron to indicate a change. You must then register the revision and upon approval, pay the fees which can be quite high. The process can take quite some time!
If you are Scottish, stick to your tartan or “plaid” (God I hate that word) which can and is worn by all and sundry!