Halyard jammed between nylon sheeve and mast head

Raising the sail today the halyard came off the groove of the nylon sheeve in the mast head and wedged between the sheeve and the inner cast iron mast head. It is jammed tight and won't move in either direction. Is there any quick fix apart from removing the mast head and then the sheeve pin?
Any ideas appreciated.

Pull the wire up as high as possible on both sides ... back and forth to un-jam.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

Thank you Matt for your reply.
I tried manipulating the wire back and forth but it was stuck fast. Even tried trying to free it with a thin screwdriver and hammer - no luck.
Had to take it to the sail-maker who managed to free it, but the halyard was badly twisted and bent. He fitted a new halyard slightly wider - 4mm which is less likely to jam.
The aluminium mast is over 10 years old so the sheeve is probably worn. Have ordered new sheeve and pin which should permanently eliminate the problem.