Hi this.to.firstName,

referral.name recommended I reach out to you. My name is this.fullName and I'm a job.title at company.name.

We're currently working on project.description, and I think there could be a great collaboration.

Do you have time for a brief phone call to discuss? If so, would any of these times work?
If those don't work, just let me know -- I can work around your schedule.

referral.name has given me your office number, which I can call. Or if you'd prefer, my phone number is my.number.

Best,
this.firstName