Below are the formal and polite equivalents (synonyms) of 'forget' or 'not remember which you can use in your business or professional pieces of writing.
These synonyms should only be used when you want to tell somebody about not doing something which you should have done, not about not being able to remember something which you did.
Using 'fail' instead of 'forget' will make you (or your business/organisation) sound a little less incompetent when talking about the thing you didn't do.
'We failed to check if the software was working before the presentation started.'
This is basically a more formal way of saying 'fail'. And like 'fail', it will make you (or your business/organisation) sound a little less incompetent when talking about the thing you 'forget' to do. I personally would use 'fail' instead of this.
'He neglected to inform them about the change to the time of the meeting.'