A few yrs ago my company changed the brokerage used for retirement; can I roll my 403b from the "old" brokerage into the current one even though I'm at the same job?

My company used Vanguard for 15 years, and five years ago, they switched to Lincoln Financial; to make it easier, I'd like them all in one brokerage; normally, you need to leave an employer before rolling over the 403b into another retirement account, but in this case I'm at the same employer BUT it's an "old" 403b at Vanguard I want to roll over. Thank you!