For as long as organizations have been using Salesforce to track fundraising, this has been a frequently asked question. 

Nonprofits typically configure their Salesforce instance so contacts fall in to two buckets, Individual (typically with an attached Household) or Organization. This is all well and good until you are faced with a situation where a single contact legitimately belongs in both buckets. Here's a common scenario:

John Jones owns Mellow Johnny's Bikes. 

Mellow Johnny's Bikes is a proud supporter of your organization with their own history of giving to your organization from the company's funds. John Jones and his wife Melissa have now decided to write a personal check to support your organization in addition to the gifts the organization gives as a company. In the Nonprofit Starter Pack, if you simply go to John's record and enter a new gift, that gift will be counted as a gift from Mellow Johnny's Bikes and will appear on the Account's summary fields. 

There are a number of approaches you can take to keep John's association with Mellow Johnny's Bikes while separating the giving history. The most important thing is consistency. Whatever you decide to do, do it each and every time. 

Some organizations will create a contact record that represents the individual at home, and a contact record that represents the individual at work. This is typically not recommended unless careful steps are taken to make sure it's extremely clear that the two contacts are the same person. As members of your organization interact with John, there will be activity history on both records. 

Approach 1: Make John an individual contact and connect him to the organization via Affiliation

With this strategy, John appears like any other individual donor. Any gift made directly from John's contact record is considered a personal gift from John and/or Melissa as members of the same household. John is now associated to Mellow Johnny's Bikes through an affiliation record as an employee of the company. The mailing address/email address for Mellow Johnny's can be added to John's contact record as work information, and then the organization can adjust communication accordingly. 

When John makes a gift it's clear by looking at the Account on the gift that the gift is from John personally. When Mellow Johnny's makes a gift it's clear from the Account on the gift that it's a company gift. Roll up summary fields are accurate between the company and the individual.

The disadvantage of this approach is that organizations will have to be sure they are reporting on Affiliations to get a list of company employees, not simply looking at Account contacts.

Follow these instructions to change a contact from an organization to individual. 

Approach 2: Use Roll up Settings to control who gets credited for gifts

With this strategy, John remains in the the Mellow Johnny's Bike Account, but he is also associated with a Household record. 

The key here is the configuration on the Household Settings tab in the Rollup Settings section. You can either create a Record Type that is unique for individual vs. organization gifts, or have a value in the Opportunity Type picklist field that indicates whether the gift is from an organization or individual.

Then you could create gifts with the Individual Gift type that are linked to John Jones through the Opportunity Contact Role but they won't appear on the summaries for Mellow Johnny's Bikes account.