[help] territory issues between old dog and adopted dog

Hello!I've a 10yo F dog who's super chilled and docile (with a smidge of dementia): Missy. Recently adopted a 9yo F who's very cute, timid and loving: Olive.Missy is generally OK with Olive. They both sleep on my bed tonight and have had some adorable cuddle naps. But tonight Missy has been growling at Olive if she comes near her, and a moment ago she nipped Olive.Do I let Missy assert this dominance so that Olive can find her place in the 'pack'?Do I punish Missy?Missy and I have been through a lot together and are very close, I want her to know I still love her and that she isn't being replaced. I also want her to know that Olive is a new family member and needs to be accepted.Help!! via /r/dogs http://ift.tt/2s8MeRD