If this print is being float mounted and has previously been in a tube, won't it need flattening before framing? I'm sure during this process they can remove the damage?

If you have a sale pending and have already agreed a price, I would offer a partial refund for the damage.

Ive had the same issue - a small OG turned up with a big crease and, under instruction from the artist did the following :-

Flat brown paper - 2 sheets, 1 iron - medium heat ( NO STEAM )

Place the brown paper either side of the print - make sure the brown paper is flat and doesn't have ridges in it or you'll end up with something resembling a McCoys Crisp

Use the iron on a medium heat and apply some light pressure over the damaged area - avoid the actual print if you can and just iron the border. Don't leave the iron in one spot for too long and lift the brown paper and inspect the crease before going for it again - just to make sure the paper isn't sticking or the print getting too hot

I did this 3-4 times and then after that leave the print sandwiched between 2 flat boards for a couple of days. Once removed, the crease will be almost invisible - place in a portfolio or somewhere where it can be left to rest for a couple more days and the crease will have disappeared

As I say - I have actually done this - I was very wary of making the iron too hot or putting too much pressure - my piece was small enough to be flattened between the pages of a book. When I removed it, even though the crease could still be seen if you looked hard enough for it, I was happy enough with the result - when i then went back to the piece about 4 days later I couldn't see the crease at all !!

I would always recommend using a restorer if the piece is expensive or the crease infringes on the actual image but basic restoration isnt as difficult as you might think......still f'kin scary, just not hard to do

nb. I was advised not to use steam or water - as it could cause ripples