3D File Modification Needed

I'm seeking a skilled 3D designer to modify an existing STL file. The original designer is unresponsive, so I need someone who can step in and complete the task quickly.

Requirements:
- Change dimensions of the existing model
- Correct any errors in the current design
- Add additional support posts as required

Ideal Skills and Experience:
- Proficiency in 3D modeling, particularly with STL files
- Experience in making precise modifications and corrections
- Ability to work quickly and efficiently
- Access to and familiarity with 3D modeling software

Please provide examples of similar work done and an estimated completion time.