Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 14; Flight Crew Type 25346
Situational Awareness
Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance
Flight Crew Returned To Clearance
Environment - Non Weather Related; Human Factors; Procedure
On the arrival into ZZZ; ATC commanded a descent; which I selected Level Change; frequency change and then cleared for the RNAV XXR Approach. After reprogramming the approach from the left to right and briefing; I failed to select VNAV before busting the 7;000 feet restriction at ZZZZZ. We Immediately disconnected the autopilot and returned to 7;000 feet. The remainder of the approach was uneventful.Prioritizing the sequence of events. Basic piloting. Having flown little in the last 90 days; my proficiency level is not as it normally is. Be aware of this and that I am in the Yellow.  Work harder at staying in the Green.
During the arrival to ZZZ; ATC requested a descent. PF selected Level Change to increase descent rate. A runway change from expected Runway XXL was to Runway XXR and the new approach was programmed. Approach clearance was received. I noted that we were still in Level Change and not in VNAV and that we were low. PF immediately corrected. Visual approach concluded the flight without further incident.PF and PM mitigate LNAV/VNAV distractions of the busy approach; runway change; etc. I; as PM; should have verified the vertical mode.
Air carrier flight crew reported experiencing an altitude deviation during approach. Lack of flying and proficiency were contributing factors.