A paper regarding Lambert's Problem states the following:
When the geometry of the radius vectors is fixed, there is only one free parameter left that wholly defines the transfer time between r1 and r2. In the original formulation, such parameter is the unknown semimajor axis a. In general, once a suitable parametrization of the orbit passing through the given points is obtained, it is possible to rephrase Lambert's problem in terms of the evaluation of the parameter's value, such that the corresponding orbit is characterized by a transfer time that exactly matches the prescribed one.
From this statement in the above paragraph: "...once a suitable parametrization of the orbit passing through the given points is obtained..."; is the definition of "parametrization" to find some parameter other than the semimajor axis that is more suitable, or is it referring to some specific process?
