Reverting FMC from DES mode back to CRZ mode

[LRW 42]

I made a flight from Hong Kong VHHH to Cairns YBCS and ran into an issue where I accidentally got into Descent mode and couldn't get back to Cruise mode. I had made a Step climb from FL350 to FL370 but wanted to descend back to 350 because of unexpectedly large headwinds at 370. I don't remember the exact sequence but I think I set the MCP to 350 and then selected LVL CHG (I don't remember if I set the CRZ ALT on the CDU to 350). Anyway, it went into descent mode and show a very gradual descent for the next 2000 nm. At that point I couldn't get it back to CRZ. Entering 350 in the ECON CRZ window had no affect. I ended up changing the last waypoint preceeding where I thought TOC should be to FL350 to get rid of the RESET MCP ALT messages

1. What procedure should I have followed to descend to 350 and resume cruise? (can Descent mode be avoided?)
   
2. After hosing up the FMC, what would be the correct procedure to recover the flight plan.
   

Thanks

[rsvit 16]

1. Open FCOM vol1 at page SP.11.18 (248 page of the doc). There you can find right procedure.

[LRW 42]

1. Open FCOM vol1 at page SP.11.18 (248 page of the doc). There you can find right procedure.

 

Thanks. I was in the neighborhood but didn't go far enough. I made it to SP.11.16, Intervention of FMC Cruise Altitude during VNAV Cruise, but I didn't want early descent, which is what ALT INTV would have done.

 

Executing it from the CRZ page is what I obviously didn't do but should have done.