Make all the asssociations with the post pleasurable. Reward her with a favorite treat when she uses it. Have her chase a string or a toy around the post or attach toys to it, which will result in her digging her claws into it. Eventually she will learn to love it and regard it as her own. It's also a good idea to put a post where Kitty sleeps.
Cats like to scratch when they awaken, especially in the morning and the middle of the night.
If space permits, a scratching post in every room of the house is a cats's delight. The most important place is the area of the house in which you and Kitty spend the most time. I have many sisal posts in my house, yet often in the morning my cats line up to use the one in the living room. If at first Kitty is reluctant to give up her old scratching areas, there are means you can use to discourage her. Covering the area with aluminum foil or double-sided tape is a great deterrent.