Ask HN: What to do if your first customer ask for shares of your SaaS?

so I did some consulting works for a company, making software to help them doing their business so that they doesnt use excel to tracking everything, like invoice, a transaction progress, delivery, accounting parts and etc.

and I see a chance that this piece of software could be sold again as saas

problem is this first customer think that to do that I need to give them some share since I learn about the business area and business process from them, how is the correct way to handle this?

I know this is my mistake I should act as a saas company/startups since the beginning instead doing a software consulting job

from the story that I found the internet one of the over is giving them one time purchase or lifetime update instead subscribing like any other users

iirc some startups do this for their first 10 customer

and also for the notes the boards at the company that I do the consulting jobs, say that they have many relations and connections about the same type of company and this boards could introduce me and gives me lead to more users currently I only know them