Internal Roof Amendment and Removing 4x2 Collars - Advice Needed

[bongobus1]

hi, i have a 70s house with 4x2 rafters and tiled roof, 2 heavy duty purlins and 2 collars

these collars are 4x2 and in the way

i know others have done loft conversions same house style and obviously wouldnt have in the room

my question is if these are structural albiet they are long and only nailed how can they remove

i would like to remove one personally

[tileclipproman]

cut them off flush with the rafters then run a stud wall along to support the purlins,transfer the collars to ceiling height along entire lenght of roof,thats what I would do.