[Gunna01]

I have designed a Travel Request form that gets assigned to a specific user, we will call them User A, who books the travel after the case has been approved.

I would like User A to be able to reassign the case to User B for some cases.

User A only books travel related to sales and training of staff
User B books travel it relates to a company funded Industry event where be have a booth.

[ashkufaraz]

You can use supervisor for do it
http://wiki.processmaker.com/3.0/Process_Supervisors