Edit phone number in phone app Is there a way to edit a manually dialed phone number before re-dialling? Occasionally I have a typo in the number or forgot to add the country code prefix. 

The only ways to handle this I know so far is 


write down the number and re-dial, or
copy the complete number, paste into a notes/text app, edit there, copy again and paste into the phone app. 


Not exactly user friendly.
I'm afraid you are correct in your assumption, once a number has been typed and a call initiated, it is not able to be edited within the phone app directly, and needs to be either sent to a new contact where you can then amend the number, or cut/paste elsewhere to allow you to make changes.