The following is taken from the Big Mango forum
First, run the old one-click startup web server.exe. Then, open the mysql database management navicat program that comes with the tool in the folder of the old end, select Connect, and in the pop-up dialog box, enter mangos for username and password, and fill in the link name randomly. In the dialog box that pops up, fill in mangos for the username and password, and fill in any link name. Click OK. Open the new connection you just created, the charcters,information_schema,mangos_b,realmd,sd2,test table will appear. Right click on the charcters table and select dump sql file, save, then is double click on the realmd table Right click on the account in the table to dump the sql file. Close navicat. close the old web server. (The old end can be deleted now)
Install the new end, run the one-click startup web server.exe on the new end, open navicat as above, right click on the charcters table and select run batch task file, select the charcters.sql file you just saved. Similarly run the batch job file on the account table under realmd and select account.sql . Exit navicat, run one-click start wow server.exe, and enter your previous account into the game.