Switching Character Sheets Mid-Game?

As the title suggests, my group and I are wanting to switch from the regular Warhammer Fantasy Roleplay 2nd edition character sheet to the 'Havoc' version. How do I, as the GM, do this without everyone losing their existing character sheets? Any help would be much appreciated! :)

Generally switching sheets is a pain, if the sheets dont use the same attribute names (and most dont). It is easier to create a new campaign, and manually recreate the characters in the new sheet. It sounds like a lot of work, but its less pain in the long run.

Ouch. I was hoping it would be simpler than that. :(

The easiest way to find out if and how much you might lose with the switch is to make a copy of the game (include the journals) and switch the sheet in the copy. This will let you see what information might be missing without damaging your current game and allows you to plan out what to do if you do decide to switch.

That's a great suggestion! Thanks very much! :)

I've done it a few times when I  was thinking of changing systems not just sheets. It helps to tinker with a backup than the main game.

You can do that, but bear in mind there's a hidden cost to changing sheets in this way. Every character and every attribute on that character in a campaign adds to lag. It adds up, and eventually the campaign can slow down. I don't know how heavy the WFRP sheets are, but the more attributes they have on them the more likely this is to happen. When you switch sheets, the attributes from the old sheet are still there, in the character sheet - you just cant see them. So you can end up with two sets of attributes, half of which aren't being used but still add to the 'weight' of a campaign.   If you dont have too many characters, and dont have a lot of monsters and npcs that you convert in the same way,  it might not have much effect (you do need a LOT of attributes to have this effect). But if you have a lot of sheets, and the sheets have a lot of attributes, it's better to start fresh. 

Well, since Roll20 is currently not letting me launch my game, I can't really fiddle around with it to much to see the impact. What I might do (when Roll20 stops being difficult) is simply have everyone copy the info from their sheets and just delete those characters, then re-do them with the new sheet. It's simply not possible for me to start a completely new campaign at this time.