Not sure about legalities but...
Open the pdf in Acrobat pro and outline the fonts save as a copy.
Open the original pdf in Illustrator and remove the heading with the font you do not have.
Open the outlined pdf and copy the outlined heading to the original pdf in illustrator.
Its a work around, this way only the font that is missing is outlined and the rest is kept as fonts.
Save the file either as an illustrator file or back to a PDF again.