A regular customer will only speak to me. How do I stop becoming the whole service?

The customer heard my colleague answer and said, “I’ll call back when she’s there.” My colleague was ready to help with the order.

I work in a furniture showroom. I helped this customer choose a table last year, and since then she asks for me whenever she buys something. That was pleasant at first. Now she waits beside my desk while I’m serving someone else and leaves messages on days I’m away.

She isn’t aggressive. She says I understand her taste and she doesn’t want to explain it again. I’ve written her preferences in our customer notes, but I also keep stepping in because it seems faster than persuading her to work with someone new.

My manager likes that she returns. My colleagues are starting to treat her orders as mine even when I’m busy.

How would you keep the goodwill while making it possible for another person to help her? I don’t want her loyalty to become a promise that I’m always available.