I don't know if the deadbolt is the same as the BE-series lever-handle lock that I worked on, so this answer is about the lever-handle one:
I just had that same problem last week! The short answer is, "No, you can't replace the cylinder," but if you are willing to do some surgery on the lock and take it apart (take a picture just before you remove each piece!), you can put a tiny opening on the cam on the back of the cylinder so a 6-pin key can go all the way into the cylinder and then go through the back.
The cam comes off in a unique way: depress the tiny brass dot in it and then turn it about 1/4 turn (maybe a little more or less, I don't remember exactly) and it will come off. You can then rekey the cylinder to your key and, as I said, make that little hole in the cam. To make the hole, I used a Dremel rotary tool with a 1/16" diameter bit. To figure out exactly where to make the hole, I put some lipstick on the end of my key and pushed it all the way into the keyway before I took the cam off. (You could achieve the same thing by sharpening a straight piece of piano wire or spring steel wire, pushing it through to the back of the keyway and wiggling it a lot to make scratch marks.) Keep your hole as small as possible so you don't weaken the cam. Assemble everything back together and you can now use your 6-pin key.
I'm being a little flippant here. The mechanism inside that lock is pretty complicated. I'm a locksmith with over 40 years experience, and while it took me only a few minutes to make that hole and rekey the cylinder, it took me about an hour to figure out how all the pieces that connected to the motor fit back into the case so they would allow the outside handle to engage the lock when the motor activated, how the wires needed to be put back in around the edges and not bind against anything, and finally to get the cover back on.
Answers & Comments
I don't know if the deadbolt is the same as the BE-series lever-handle lock that I worked on, so this answer is about the lever-handle one:
I just had that same problem last week! The short answer is, "No, you can't replace the cylinder," but if you are willing to do some surgery on the lock and take it apart (take a picture just before you remove each piece!), you can put a tiny opening on the cam on the back of the cylinder so a 6-pin key can go all the way into the cylinder and then go through the back.
The cam comes off in a unique way: depress the tiny brass dot in it and then turn it about 1/4 turn (maybe a little more or less, I don't remember exactly) and it will come off. You can then rekey the cylinder to your key and, as I said, make that little hole in the cam. To make the hole, I used a Dremel rotary tool with a 1/16" diameter bit. To figure out exactly where to make the hole, I put some lipstick on the end of my key and pushed it all the way into the keyway before I took the cam off. (You could achieve the same thing by sharpening a straight piece of piano wire or spring steel wire, pushing it through to the back of the keyway and wiggling it a lot to make scratch marks.) Keep your hole as small as possible so you don't weaken the cam. Assemble everything back together and you can now use your 6-pin key.
I'm being a little flippant here. The mechanism inside that lock is pretty complicated. I'm a locksmith with over 40 years experience, and while it took me only a few minutes to make that hole and rekey the cylinder, it took me about an hour to figure out how all the pieces that connected to the motor fit back into the case so they would allow the outside handle to engage the lock when the motor activated, how the wires needed to be put back in around the edges and not bind against anything, and finally to get the cover back on.
Good luck!