Application showing 2 different brands

I have been checking other people who have tried to solve the same problem but couldn't find anyone in a similar situation really:

Our company has a number of applications and we share a common branding for all of them, displaying our company logo at the top-left as usual. The problem is that we are selling some of those applications to other companies and they want to show their logos as well.

I have been trying different options but I can't seem to find any that really works as in all of them the customer logo seems out of place.

Has anyone had to do something similar?

Many thanks.