Disassemble the pool table. To avoid damage to the slate, a pool table should never be moved in one piece. The slate is the playing surface of the table. As you are taking the table apart, mark the pieces in a hidden area to help you put it back together once you get it upstairs. Keep all of the pieces together and in a safe place so that nothing gets lost.
Enlist the help of 3 to 5 friends or neighbors. The slate alone typically weighs over 150 pounds. Carry the slate up the stairs, keeping it in a vertical position the entire time. Slate should never be transported in a horizontal position because the seams between the slate will be more likely to pop.
Carry the rest of the pieces of the pool table up the stairs, including the rails (the padded edges of the table) and the cabinet (the legs and frame). Although these pieces aren't as heavy as the slate, you will still need assistance moving them.
Reassemble your pool table once you have all of the pieces upstairs. Take your time, and use the markings you made during disassembling the table to guide you. If you rush reassembly, you may end up mixing similar pieces. Once you have the table put back together, call a professional to re-level the table for play. Anytime a pool table is moved, it should be re-leveled by a pool-table specialist.