Could anyone correct my reference letter please?

To whom it may concern,

 
Noelia has been was engaged in doing (add one of these as well: administrative/nurse/auxiliary/veterinary) relief work for LC Veterinary Clinic from March 8, 2004 to April 1, 2014.

Noelia has done an excellent job [or "Noelia has performed excellently adapting..."] adapting to our clinic's procedures. She picks things up very quickly and is very knowledgeable.

Noelia has a very upbeat personality and works well with all staff and clients. She was is very dependable, she and will jump right in [or "...and is quick to get involved when..."] when things need to be done.

We are sorry to lose Noelia as our relief technician, but know she will excel no matter wherever she goes.