Knowing how to delegate routine tasks is a key skill for an executive. It’s one that certain personality types often have difficulty with. Some people feel a compulsion to control everything and remain personally involved in every single detail. Such people quickly turn into a one-man bottleneck and become a main limiting factor in their organization’s growth.

But inversely, there are some things that should never be delegated to underlings.

Administrative assistants are great. But a common mistake is to delegate contact or communication with a peer to an assistant. You can’t delegate relationship. If you’re not talking to your key clients, customers, or vendors, you don’t have a relationship with them. Your assistant does.

Certainly, it’s not harmful to let a peer or client know that you will be asking your executive assistant to follow up with some details or information. It’s simply important to keep in mind that unless that contact is having a regular dialog directly with you, your relationship with them is in the process of deteriorating.

Furthermore, given all the possible channels for communication available to us now—email, mobile-to-mobile text, chat, social media, etc.—it can feel doubly strange for your key contacts to get messages from you via an assistant.

We can’t forget basic business decorum. And we can’t delegate relationships to our assistants. In many instances it is best we do the contacting ourselves.