You can achieve this with a free trial of iBackupBot 3.5.2 without jailbreaking.
1. Make a backup of your phone in iTunes
a) open iTunes
b) connect you phone with the cable
c) right click on your phone's name in iTunes
d) select Backup
2. Download and install iBackupBot (http://www.icopybot.com/download.htm)
3. Download and install "plist Editor for Windows" (Freeware) from the same address
4. Export Library/Preferences/com.apple.MobileBluetooth.devices.plist using iBackupBot
a) open iBackupBot
b) let it read your iPhone backups
c) left click on the most recent backup on the left hand side (should be the one you just created)
d) browse to Library/Preferences/com.apple.MobileBluetooth.devices.plist in the right hand pane
e) tick the file
f) go to file > export > export only the checked file > tick export with backup info
g) choose a destination you'll remember
5. Edit Library_Preferences_com.apple.MobileBluetooth.devices.plist
a) open "plist Editor for Windows"
b) open the Library_Preferences_com.apple.MobileBluetooth.devices.plist file you just exported
c) edit the string immediately after the Name key (not default name), e.g.
d) save the file (overwrite the old one)
e) close plist Editor
6. Import the revised com.apple.MobileBluetooth.devices.plist
a) go back to IBackupBot
b) click file > import > Library_Preferences_com.apple.MobileBluetooth.devices.plist.info (note the info on the end)
c) Right click on the most recent backup on the right hand pane
d) click restore this backup
e) or I think you can restore from backup in iTunes instead of steps c and d
USE AT YOUR OWN RISK!