Foreclosure for equitable relief, procedure

1. Waiver of foreclosure. The municipal treasurer, when so authorized by the inhabitants of the municipality, or in the case of a city by the legislative body thereof, may waive the foreclosure of a tax lien mortgage by recording a waiver of foreclosure in the registry of deeds in which the tax lien certificate is recorded before the right of redemption therefrom shall have expired. 2. Form. The waiver of foreclosure must be substantially in the following form: 3. Foreclosure of tax lien mortgage. If said tax lien mortgage together with interest and costs shall not be paid within 6 months after the date of recording the waiver of foreclosure thereof, the tax lien mortgage may be foreclosed in an action for equitable relief. 4. Right of redemption. In such action the court shall provide a period for the exercise of the right of redemption from the tax lien mortgage which shall expire in not less than 90 days from the decree of the court and in no event before the expiration of 18 months from the date of filing of the tax lien certificate in the registry of deeds as provided in section 942 .