First of all whenever you are dealing with high voltage you should contact the power utility and an electrical contractor. There are just those jobs that are not well suited to the do-it-yourselfer. The problem with this type of repair is that it must be done live unless the power utility can shut off the power at the pole. By working around live wires outside the home you could easily be killed. As to the actual job, it depends upon the type of mast. Generally speaking there are two types, wood and conduit. Wood masts are often mounted through the side of the home with bolts. When the wood rots out it is best to replace it with a metal mast. If the mast is metal conduit and is just bent you may be able to pull it straight and use guy wires to keep it straight. The big thing is that the wires coming to the home have a single cable included that is supposed to be anchored to the house if this wire comes off the weight of the wire is placed on the drip Loop. Once again it is best to get the help of a professional.