Can I change my business structure for business purposes while a a suit is pending?

Depending on what kind of change you are thinking of making to your business, I don't believe a lawsuit automatically prevents you from making the change, HOWEVER, if you are a partner in a partnership (for example) and wish to change your partnership into a corporation, the change will have taken place AFTER whatever circumstances led to the lawsuit being filed, so you will still be considered a partner for the purposes of the lawsuit. In other words, you can gain whatever benefit can be gained from changing the nature of your business, but NOT retroactively.

Unless there is a court order restricting the transfer of your property or assets, you are permitted to do anything you would want to with your business, including reorganizing it.