When companies approach branding firms like Siegel+Gale for guidance on merging two corporate or product brands, the request is typically for us to develop a name, logo, endorsement strategy and story for the new merged entity. In many cases, however, it’s not the right move to simply create and launch a new brand identity overnight. The job is not done with the introduction of some new branding elements.

Merging companies and brands is a process. It’s about transitioning equity, shifting perceptions and migrating customers. It must be done carefully, strategically, with the full support of business, marketing and brand management resources within a company. If not done right, companies can squander brand equity and lose customers. In addition, competitors can steal market share, company cultures can be destroyed, and, the value that the M&A deal was supposed to create can get undermined.

The problem is that, in most cases, companies lack a clear business and marketing migration plan and resources to support an effective brand migration. This is probably a result of the way mergers and acquisitions happen: executives who have little experience managing brands work behind the scenes to make an acquisition. The acquisition is announced and there is no qualified team in place to manage the transition. Merging brands is treated as an afterthought.

The truth is that proper brand migration requires the right people, planning, investment, measurement and commitment.

Here are six necessary steps for merging brands properly:

1. Establish a cross-functional team of three to five business, marketing and branding staff who will oversee the migration for 12 months.

2. Identify the synergies between the two brands and the ways each brand creates real value for customers. Don’t just slam the two brands together into something new and start advertising.

3. Architect a migration plan that outlines exactly what role each brand will play over the next 12-24 months, and how each will deliver value for customers. What exactly will each brand bring to the equation? Which employees will represent which brand? (Careful planning, in particular, is an area that few companies invest in.) Include metrics to measure the effectiveness of the migration.

4. Develop a name, logo, endorsement strategy and story for the new entity. (Note: It’s not just about a new name and logo. It’s about creating the right communicative relationship between the two brands in digital and print communications and across all touchpoints.)

5. Communicate, communicate, communicate. Make sure customers understand the role that each brand plays.

6. Manage the migration over time. Be prepared to evolve the identity as the relationship between the two brands shifts.

Lastly, there may be some cases where it makes more sense to keep two brands separate. Some companies have a tendency to simply swallow every brand they acquire without thinking things through. This is not always the best decision—but executives sometimes forget it is an option in the excitement of the merger or acquisition.

The option to keep brands separate should be kept on the table during the migration planning process and weighed carefully. Without a clear and well-grounded rationale for merging two brands, your company runs the risk of ignoring that old, but good adage: “first, do no harm.”