I wouldn’t do anything previously said in this thread.
You need to take the amp out of the chassis to asses the situation. Wear some protection as the chemicals inside tubes aren’t good for you.
I’m assuming the sockets are in a PCB mount, but shouldn’t matter. Figure out the tube orientation and between pins 1 and 9 should be a small gap where there are no pins. This is where you will slide a small flat head screw driver under the bottom of the tube to pry it up GENTLY!!! The tube should slowly work its way out. Please be careful if the PCB and tube socket. The bottom of the tube should be robust enough to take the prying pressure.
If this doesn’t work…
Cut away the top part of the tube. You can probably twist it and the thin metal contacts will likely pull away from the pins use your discretion. Once the to part is removed you should see several thicker metal pins remaining. This is where you will use a pair of good pliers, preferably two pairs, (one each side) and firmly, but with finesse, pull the tube pins out of the socket. Keep in mind if you pull side to side you may bend the pins and weaken them. A few good tugs should pop the tube out.
Feel free to take pics and ask us if you need more help.