You can switch out of the carrycot but you should have it in the redlined position. Babies need to lie flat as much as possible until the age of six months and shouldn’t be in a sitting up position until they can do so themselves. Having them sitting up can negatively effect their breathing and heart rate and lying flat is the safest position for them. It’s also better for their hip and spine development.
I changed mine to the seat from 4 months, best thing ever he loves it now being able to look around at everything. There are 4 positions it sits in so I just keep it within the 2 most laid back positions x
I have my little girl is 13 weeks. It basically lays flat any way but she likes looking around xx