No worries. The airline began to involuntarily upgrade F/Os ("displaced") when captain staffing levels became critical some time ago. This coincides with the moment they started allowing the hiring of DECs.

When it looked like I could hold my preferred base as captain (plus it was time to start making cash), I "proffered to displace" to captain, which is a formal request that my seniority allow me to be displaced to captain before those junior to me, since these displacements occur starting from the bottom of the seniority list and work their way up.

I did this, rather than voluntarily bidding for captain, because I could take advantage of the benefits that come with displacement (i.e. no 24-month "training freeze" commitment to the equipment I was displaced into).

I had a fifteen years of 135/91 corporate in my former life.