Excuse me,

Pardon me,

Sorry to interrupt,

May I interrupt (for a minute)?

Can I add something here?

I don't mean to intrude, but . . .

Could I inject something here?

Do you mind if I jump in here?

Getting back to the topic
Anyway,

Now, where was I?

Where were we?

What were you saying?

You were saying . . .

To get back to . . .