Use Preview to edit at PDF which asks for two different phone numbers

I need to edit a PDF which has two fields marked "Phone no.". The phone numbers should be different from each other. Preview recognizes that these fields are for phone numbers, and "helpfully" overwrites the value of one when I edit the value of the other. I've tried editing the PDF in Chrome and Skim as well, but the same issue occurred. I would prefer to avoid splitting the PDF and rejoining it (possible because the fields are on different pages) or using text boxes to cross out and list the correct phone numbers.