As an older gentleman, I've walked in and asked for a business card. I'll remark that I put it in my wallet and it becomes a To-Do item.
Do not read so much, look about you and think of what you see there.
Richard Feynman-- letter to Ashok Arora, 4 January 1967, published in Perfectly Reasonable Deviations from the Beaten Track (2005) p. 230
Call back and say you were in earlier and had a follow up question and say you can’t remember who you spoke with but it’s the (fill in the blank— guy in red shirt with black hair). They should say, “oh that’s Josh.. he’s with a customer can I take a message?” Think of a question to ask or say you’ll call back. Otherwise go back in and get a card or look for a name tag.
Like the others said I call the bank and say "I was just in and was speaking to a banker but I can't remember his name and I have a question for him." They'll then provide his name and transfer you to him and I make up a question. If you need a business card, which you probably do, then I go back in with said made up question and say "I just had another question" If he can see you, he answers the question and you ask for the business card. If he can't see you then you ask if someone could give you his business card and tell them you'll call him later.
Some bank shops expect the person to be wearing a name tag. If I can't use the approaches above (for example, if I'm entering the report at home and the bank is closed), I have entered No Name Tag Visible (or if I'm sure there was indeed no name tag, I leave the word visible off). When the report has a good description of the banker and the clothing worn, the reports have been accepted.
Could depend on the msc. Doing one for ath - One time I lost the business card and forgot her name lol! I wrote the scheduler. They let it go “just this one time”.
Maybe call the bank and say you loved the interaction you had recently with the person you just saw. Describe the person and say you’d like to work with them the next time you come in but you can’t remember who it was. Or you could also say you wanted to leave a Google review and mention that person’s name, then go ahead and leave a review on Google with that persons name so you don’t get outed as the shopper for possible later visits.
There's an off chance you can google to see if that location has a website or an ad that gives photos and names of branch staff, probably going back there is your best bet.