Stupid Question: How to take out tubes??

I know this is a stupid question, but i want to know how to take the tubes out when replacing them. I opened up my tubed preamp yesterday to replace some microphonic tubes but I wasn't sure how to do it. Do I just pull the tubes straight out, or is there a release lever on the tube socket. I dont' want to mess around with it unless I know for sure. The tubes are 6922. Thanks