To refinance your mom's reverse mortgage into a traditional mortgage so you can keep the property, you need to hold title first.  Lenders require ownership before they will approve a loan in your name.  Once title is in your name, you apply for a traditional mortgage, and at closing the new loan pays off the reverse mortgage balance.

If the outstanding balance is more than the home is worth

This is worth knowing upfront.  If your mom's reverse mortgage balance exceeds the current appraised value, you have an option most people are not aware of.  HUD allows heirs who want to keep the property to purchase it for the lesser of the outstanding loan balance or 95% of the current appraised value.  That can be a meaningful savings depending on how far underwater the loan is.

If you are acquiring the property from the estate

If there are other beneficiaries, the estate needs to sell the home to you.  That follows a standard real estate transaction process.

1. The estate's authorized representative agrees to sell the property to you.
2. You secure financing based on the sale agreement.
3. The loan proceeds pay off the reverse mortgage, and any remaining funds are distributed according to the estate.

Watch the timeline

When a HECM becomes due and payable, you typically have 30 days from the servicer's notice to communicate your intentions.  Extensions are available - up to 12 months total to sell or arrange financing - but you need to stay in contact with the servicer.  Missing that window creates problems.  Call the servicer early and let them know you intend to keep the property.  They will work with you on the timeline as long as you are communicating.

Talk to a forward lender early in the process so you understand what you qualify for before you commit to a path.

Reference: HUD Handbook 4000.1, Section VI - HECM Servicing and Due and Payable provisions.