If you mean use the recline function on the seat then no you should not use these rearfacing. rearfacing has the one angle and it locks in that position....the seats are not crash tested in the other positions rearfacing so you would theoreticaly be using your child as a crash test dummy. It is set at that angle so that the baby is forced back into the seat and the seat takes the maximum amount of impact force in a crash, if you change that you affect the impact absorpton capability. Also it will affect the ability of the rebound bar to sit perfectly flat against the back of the seat, actually I am not sure if you can alter the recline without disabling the rebound bar even? hmmm......not sure on that one. BUt IMHO not worth the risk.....My LO was quite happy still at 18 months in the reclined rear facing position...he was just turned forward facing last week as he hit 12 kilos and he actually doen't like it as he can't work out how to go to sleep sitting up...go figure! LOL....have you tried a toy bar or a mirror so you can talk to her?