How can I switch my EB-5 application over to my wife?

It depends on what stage of the process you are in. If you already submitted the I-526, the rest of the process will continue to have you as the principal applicant. There may be ways to arrange your entry and that of your wife and/or children, but you would need to carefully review your timelines, goals, and immigration history.

You probably will have to withdraw your I-526 and your wife can file a new I-526 petition. You will lose your priority date, i.e., your place in line, and you may have to execute some declaration or other written statement explaining the situation. Also, it is likely that your wife will have to sign new project agreements with the regional center.

You cannot simply substitute your wife's on your application. The only way for your wife to become the main investor is to file the new I-526 in her name. Rather than losing all the time your case already has been pending by filing a new case under your wife, if you need to attend business back home, you could do that easily enough after getting your conditional green card. All you have to do is to come into the United States at least once a year while your wife and your children reside here.

Withdraw and refile.

Have your wife be the primary applicant/investor from the beginning. You do not have to remain in the United States while the I-526 is pending as the conditional green card can be processed through the consulate/embassy. More information is needed here in order to determine if you will be able to maintain your green card status. I recommend you speak with an immigration attorney about the specifics of your case.

I am not sure what you mean by not enough time to get your green card. Once you are approved and given the visa to come to the United States and receive your conditional permanent residence, you may come and go as you please. You could attend to business back home.

If you have to leave the United States and the I-526 is pending, you can do consular processing instead of adjusting status. You cannot transfer a I-526 petition to a spouse.